Penny

Penelope "Penny" (surname currently unknown) is the show's main female protagonist. She lives in apartment 4B across the hall from her boyfriend Leonard Hofstadter and Sheldon Cooper, his roommate and friend.

An aspiring but unsuccessful actress, she was born in Omaha, Nebraska and works at The Cheesecake Factory as a waitress. Penny is one of the main female characters in the show alongside Bernadette Rostenkowski and Amy Farrah Fowler, as well as the first of the three to appear on the show.

She has been Leonard's love interest for most of the show, with the two dating briefly in the first episode of the second season, for most of the third season, and they rekindle their romance in Season 5's The Recombination Hypothesis. Despite their rocky on-and-off relationship, Leonard and Penny are good friends, and she gradually becomes part of the guys' social group.

Physical Appearance
Penny is 5'6", with blonde hair and green eyes. Her most distinguishing features are her hair, eyes, smile and bust. Her wardrobe includes casual sportswear, her Cheesecake Factory uniform, and glamorous evening gowns. Regardless of attire, her wardrobe, makeup and accessories highlight her best attributes.

Initially, her taste in clothes included skimpy shorts, low-cut tops, and bare middriffs, but over the course of the show, it evolved into more modest and flattering sweaters and pants as she got older. Her hairstyle varies, originally being long and straight, but is currently curly and a darker shade.

Background
When she first met the guys in the Pilot, Penny was writing a screenplay about a girl from Lincoln, Nebraska, who travels to Los Angeles to become an actress, but ends up working at The Cheesecake Factory instead. When Leonard asks if the screenplay was autobiographical, she replies that it isn't, because she is from a small town outside of Omaha, Nebraska.

The reason Penny moved to the apartment building in the first place is because she split with her boyfriend of 4 years, Kurt, and was thrown out of his apartment. She says she still loved him, but wanted custody of their television set. The shower in her apartment was broken at the time, and asks to use the boys'.

She is either oblivious to or completely aware of her effect on the boys, because within minutes of meeting him, she asked Leonard to retrieve her television set from Kurt's apartment, which he immediately set out to do. Penny is aware of Leonard's crush on her, and it is hinted throughout the series that some of the feelings are reciprocated.

At the end of season one, Penny goes on a date with Leonard. They are both very nervous, but nonetheless share a passionate kiss. Her apartment becomes sloppy and disorganized, but Penny appears to like it that way. Whenever Penny goes on a rebound relationship, she picks up an attractive man and then has 36 hours of meaningless sex with him over the course of a weekend; afterward, the relationship deteriorates.

In Season Two, there was some initial enthusiasm between Penny and Leonard. However, they later develop insecurities concerning their relationship. Penny was worried that she was not smart enough for Leonard, and lied about graduating from community college because she thought it would make Leonard respect her. The relationship quickly deteriorated and she goes back to dating different guys.

She gives Leonard relationship advice when he's with Stephanie and they seem to develop a deeper friendship. She also starts to become geekier. She makes inadvertent references to Star Trek, and becomes addicted to Age of Conan. She also dates Stuart, who runs the comic book store, much to Leonard's annoyance. When Penny and Stuart are making out, she accidentally calls him Leonard, and as a result, they stop seeing each other. This reveals her feelings for Leonard, who celebrates after hearing the news. When she learns Leonard planned on accompanying Sheldon on his Arctic expedition, she is visibly upset, buys him a blanket with sleeves as a farewell gift, and tells herself, after speaking with Leonard, that she wishes he wasn't going.

In Season Three, when the boys get back from the expedition, Penny was obviously missing Leonard quite a bit and kisses him passionately the second she sees him. Their relationship has a rocky start because they aren't left alone at first, and they have some trouble getting used to being more than friends. They eventually start a stable relationship, which annoys Sheldon, due to some of Penny's habits being considered annoying. Sheldon later applies his knowledge of behavioral psychology and begins to train her using positive reinforcement techniques (giving her chocolate) with a surprising amount of success in removing her "bad" behaviors.

Family
So far, the only member of Penny's family that has been seen is her father, Wyatt. Penny had a very close bond with him when she was a child, however, it is mentioned that it was a tomboy bond since he wanted another son instead of another daughter, so despite hating to get dirty, Penny tried to be good at sports to make him proud.

He used to call her 'slugger' until she bought her first training bra, and then he just stopped calling her 'slugger' altogether and didn't play catch with her anymore. Penny has also been shown to have lied to her father when she was in high school, when Wyatt explains she tried to pass off a home pregnancy test as a test for diabetes, and also tried to explain a bag of marijuana in her underwear drawer as 'potpourri'.

Several other members of her family have been mentioned too. Penny's sister is mentioned as having shot her husband while both she and her husband were drunk. It is known that she has a nephew who turned 13 in Season Two, likely the son of Penny's sister, as she is known to be married. When Christy comes into town, Penny reveals that she has a brother and at least one male cousin, as she claims that Christy slept with the former while being engaged to the latter.

Her brother also works in a meth lab, though it's not clear if it is the same brother Christy slept with. This is first hinted at in The Pirate Solution as Penny describes him as 'kind of a chemist' and told Leonard that he'll like him. It is finally confirmed in The Rhinitis Revelation, as she asks God to make her brother stop making it, but without involving the police. Sheldon implies Penny's mother is fat and in The Flaming Spittoon Acquisition  says that her mother smoked pot when she was pregnant with her.

Kaley Cuoco has said that she would like Penny's mother to appear, and for Lisa Kudrow to play her. She says that she imagines her as "a skanky, dirty, trailer trashy cougar, hitting on the boys."

Leonard
Leonard's and Penny's relationship is one of the primary topics of the series. Leonard became attracted to Penny the moment he met her and it didn't take her long to figure out that he had feelings for her. Penny shows no signs of interest in Leonard until The Hamburger Postulate when she hears of his failed attempt at a relationship with Leslie Winkle, though the sign is seen only by the audience. Despite these signs, she continues to date other men as Leonard continued to try and make her give him a chance.

She and Leonard go on a date in the finale of the first season, but they break up not long after because Penny fears he will get bored with her due to his high intelligence compared to her own. They remain friends although signs of their feelings for each other continue to show. After Leonard returns from his three-month research trip at the North Pole, Penny immediately kisses him, having missed him greatly.

They begin dating again and despite another rocky start, they are together for most of the 3rd season. They break up again after Leonard says he loves her and she doesn't say it back. They again stay friends throughout season 4 but it is strained as Penny struggles to control her feelings for Leonard as well as her jealousy towards Priya. While drunk, she admits to Raj that she shouldn't have ever broken up with Leonard.

At the spur of the moment in The Recombination Hypothesis, Leonard asks Penny out on a date after he imagined what getting back with her might be like. Their real date ends successfully and they agree to take their relationship slow in The Beta Test Initiation. In later episodes they appear to be still together.

In The Launch Acceleration, Penny suggested that they move up their relationship and get intimate, however, Leonard ruins the mood when he asks her to marry him. They later meet and Penny, unlike their first break-up, managed to reject his proposal and still stay in the relationship with him. During The Countdown Reflection, there was some friction between the two of them about the proposal, but when Howard was being launched they were holding hands to comfort each other.

Sheldon
Penny and Sheldon constantly irritate each other and get on each other's nerves. Sheldon is quick to take shots at Penny's intelligence, job, and failing career while Penny throws off his personal routines, such as during

The Panty Pinata Polarization when Penny messes up Sheldon's laundry night. Despite their differences, Sheldon and Penny are very close, and are quick to help each other. They have taken care of each other on multiple occasions, often times doing things they really don't want to do to make each other feel better.

Major examples are when Penny takes care of Sheldon when he is sick and when she lets him stay at her apartment when he gets locked out, even letting him sleep in her own bed. Sheldon was also quick to come to Penny's aid when she called for help after falling in the shower and dislocating her shoulder, going so far as to drive her to the hospital, despite not knowing how to drive.

Many of these occurrences end with Penny singing the song "Soft Kitty" to Sheldon to make him feel better; Sheldon sang it to her on one occasion as well. One of the biggest examples of their friendship is that despite his own rule of avoiding physical contact with people, Penny is one of only three people Sheldon has hugged who aren't members of his family, the only others being Wil Wheaton and Amy Farrah Fowler. Penny seems at times to act like a "surrogate mother" to Sheldon, with Leonard being the father. During the time Penny and Leonard were together, whenever they fought like a divorced couple, Sheldon acted like a child caught in between them.

Howard
Upon meeting, Howard constantly hit on Penny in ways that made her deem him "disgusting". Their dynamic remains the same for the most part throughout the series but begins to change when Howard begins to date Bernadette. Although Penny is not a fan of him, she and Howard maintain a friendship, although they rarely hang out outside the group. Howard flirts with Penny much less and becomes more casual towards her after he begins his relationship with Bernadette, which Penny obviously enjoys, although she still pokes fun at him.

Raj
Like with all other women, Raj is unable to speak to Penny unless he is drunk or on medication. They hang out within the group a lot and Penny occasionally attempts to tease him into talking to her. Raj begins to like Penny as the series goes on and the two end up getting drunk and appear to have slept together.

Later Raj tells Penny that they did not have sex, and in clarification, he tells her that when she helped him put on the condom, he ejaculated prematurely. Raj asks Penny not to tell anyone and Penny promises to keep silent. Raj attempts to actually date her but she tells him she just wants to be friends. Despite their rough past, Penny attempts to find a girlfriend for Raj and comforts him when he may need it.

Bernadette
Penny and Bernadette worked together at The Cheesecake Factory, until Bernadette received her PhD and becomes a microbiologist, and are close friends. She is the first person outside of the group of guys that Penny is seen to hang out with on a regular basis. They enjoy hanging out at Penny's apartment, comfort each other, and go out together.

They also hang out with the guys together once Howard starts dating Bernadette. In the episode The Countdown Reflection, because Bernadette wants to get married to Howard before he goes into space, Penny, along with Amy, Sheldon, Leonard and Raj get ordained as ministers to enable her to officiate the wedding ceremony.

Amy
When Bernadette and Penny were having a sleepover, Amy injects herself into Penny's life by getting herself invited. In no time she claims that she and Penny are best friends and calls her "bestie". When she initially hangs out with Penny and Bernadette her lack of social skills make it somewhat awkward, but as she spends more time with them they bond and the 3 become their own group as a counterpart to the group of guys.

The two gradually form a tight friendship and continue to spend more time together and are quick to aid one another whenever the other needs it. Amy is aware that Penny is the planet that her social life revolves around and quickly reverses her course if she is mad at her or is annoying her. Amy gave Penny a large ugly picture of the two of them to celebrate their friendship.

At one point she realizes that Penny hates it, Penny rushes over to Amy's apartment to rescue their friendship and rehangs the painting in her apartment. In The Shiny Trinket Maneuver, when Amy had her argument with Sheldon, Penny takes Sheldon to the jewelry store to buy a gift. Sheldon ends up getting Amy a tiara. Penny is more than happy putting the tiara on Amy, which makes Amy ecstatic. In The Weekend Vortex, Amy confides in Penny when she had an awful time at her aunt's birthday party because Sheldon backed out on his promise to attend to play Star Wars: The Old Republic, an MMORPG.

Penny gets them to play quarters where the loser will need to drink beer. Amy turns out to be very good at the game from all the time she spent as a child throwing coins wishing for friends, and as a result, Penny got drunk. She convinces Amy to make a scene and the two barge into the opposite apartment as the guys are in the middle of their marathon. Amy fails to keep up her ruse of leaving Sheldon for a make-believe character named Arman, and Penny comes to her rescue by telling Sheldon the truth.

Trivia

 * Penny is 22 years old at the beginning of the show (in the early fall of 2008, when The Barbarian Sublimation aired), which means that she is the youngest of the gang. Penny is a Sagittarius, meaning she was born between November 21 and December 22. In The Prestidigitation Approximation, Howard does a fake magic card trick in which the sum of the digits of one's birthdate, excluding the year, are used to get the number of the card to be selected. Penny turns over the fifth card, making her birthday in the span of the Sagittarius one of four possibilities: November 30th, December 2nd, December 11th, or December 20th. Penny's birthday likely is November 30th (1+1+3+0=5), as it would match the birthday of Kaley Cuoco (Saturday, November 30, 1985) exactly. Observe that the only possible birth date of Penny would be Monday, December 2, 1985 if one alternatively interprets the rules of Howard's card trick as requiring one to turn over the card corresponding to the sum of the digits of the month and adding the day. Though David Underhill refers to Penny as a "gorgeous 22-year-old" in The Bath Item Gift Hypothesis (airdate December 15, 2008), he could have simply estimated her age, as it certainly appears to be close to Christmas and the episodic events probably span days rather than weeks (if one were to ignore the hypothesis that the airdate is reality in the show).
 * Sheldon once calculated that Penny dated an estimate of 193 (±8) men and had sex with approximately 31 of them in the episode The Robotic Manipulation.
 * Penny grew up on a farm and rebuilt an entire tractor engine all by herself when she was 12.
 * Penny was a Junior Rodeo champion.
 * The previous occupant of Penny's apartment was a 200 pound transvestite named Louie/Louise with a skin condition who works as a police officer according to Sheldon. He was seen during the episode The Staircase Implementation.
 * She is the only member of the main set of characters whose last name has not been spoken or revealed, but Bill Prady has said it eventually will be.
 * Penny claims to be a vegetarian, but will eat fish and the occasional steak.
 * Penny often smells like either vanilla (because she wears vanilla oil) or cheesecake (because she works at The Cheesecake Factory).
 * Penny's acquaintance Christy, could be a reference to Kaley Cuoco's time on.
 * Penny eats Chinese food with a fork and double dips her egg rolls (unappealing attributes, according to Sheldon).
 * In The Staircase Implementation, it is revealed that Penny was almost a teenage mom.
 * Penny is very kind, but can become extremely fierce when provoked. She has yelled at Sheldon, Raj and Howard when they annoy her too much, and Leonard when she's angry.
 * When under pain medication, Penny exhibits some of Sheldon's behaviors.
 * Penny believes in psychics, ghosts, astrology, voodoo, and other 'superstitions', but not healing crystals.
 * A reference to what may supposedly be her full first name was made in The Barbarian Sublimation, in which her online nickname to play Age of Conan was Queen Penelope.
 * Penny went to community college, but dropped out for unspecified reasons.
 * A running gag of the show involves Sheldon knocking on Penny's door and saying her name after every three knocks. He repeats this thrice or until she answers the door. This is one of the most frequent scenes in the show.
 * With the exception of his family, Wil Wheaton, and Amy Farrah Fowler, Penny is the only person Sheldon has hugged.
 * Penny is known to be a moocher. When Sheldon's mom pointed out her disapproval of a top belonging to Penny, she said that she had received free drinks by wearing that top. It is also known that while she was dating Leonard, she never paid for her movie tickets. She also gets free meals from hanging with the guys since her portions were always paid by Leonard, she said they were loans but deep down she knew Leonard would not ask her to pay back. She also gets free internet by using Sheldon and Leonard's Wi-Fi - which leads Sheldon to regularly change the password to ones which accuse her of freeloading.
 * She turned down Sheldon's offer for a date (although Sheldon only asked her to make Amy jealous) and revealed that her mother smoked pot while pregnant with her in The Flaming Spittoon Acquisition.
 * Penny was actually a bully in high school, making fun of a girl with a stutter and taping another girl up and leaving her out until the next morning.
 * In Sheldon's attempts to get information or help from Penny, he usually ends up insulting her when referring to her personality or actions.
 * Penny is remarkably adept at games in general, excelling at Halo, Age of Conan, and most recently Chess, check-mating Leonard on her first try (though the latter may have been because, as Sheldon has pointed out, Leonard is terrible at chess).
 * Penny is shown to be abnormally strong for a woman, as she was able to give Howard a bruised face and a broken nose with one punch.
 * While Penny has a pleasant outgoing personality, Katie from the unaired pilot opening was meaner and mocked them. Penny does have a temper and some of this personality came over from the first pilot since when she's really mad.
 * Penny owns a red 1980s Volkswagen Golf Mk1 Convertible. It is featured in several episodes. The car appears to be in a bad condition, which is not helped by Penny, who pays no heed to the warning lights of the car. While sitting in her car, Sheldon will continuously remind her that the 'Check Engine' warning light is on, an action that irritates Penny tremendously. When Penny dislocates her arm in one episode, Sheldon drives her to the hospital in this car, driving at an extremely slow pace. In the same episode, Penny infers that she may have crashed her car once while talking to Sheldon, when Sheldon asked her where is the passenger-side wing mirror, to which she replied in a parking lot in Hollywood.