The Bath Item Gift Hypothesis

"The Bath Item Hypothesis" is the eleventh episode of the second season of the  The Big Bang Theory. This episode first aired on December 15, 2008.

Summary
Sheldon undergoes obsessive preparation to exchange Christmas presents with Penny, whose Christmas to Sheldon goes beyond Sheldon's wildest dreams. Penny starts dating a handsome physicist.

Extended Plot
Wizard physicist and all around hunk David Underhill starts working with Leonard. While eating lunch at the Caltech cafeteria, the topic of discussion was how does keep his uniform clean? The first proposal is that he flies through our. But what if it is indestructible mustard or Kryptonian sweat from a tether ball game in the miniature Kryptonian city of ? Luckily they hypothesize that there is a handy Kandorian nearby. Enter the recent winner of the Macarthur Genius Grant: David Underhill whose work in galactic invalidated most of Leonard’s work. David is quite good looking and Raj develops a crush on him. David ask a favor of Leonard to work with him on a project. Leonard agrees enthusiastically.

Leonard arrives at the apartment, missing Wii Bowling Night. Dave is very cool, as he is a Black Diamond skier, collects vintage, and does a spot-on impression of Stephen Hawking having phone sex. Dave and Leonard are getting along very well and are going to the gym in the morning. Penny asks if the guys are putting up a to which Sheldon explains. "We do not celebrate the ancient pagan ritual of . Sheldon explains, "In the pre-Christian era, as the approached and the plants died,  brought evergreen boughs into their homes as an act of sympathetic magic to guard the plants and preserve their essences until spring. This custom was later appropriated by northern Europeans and eventually becomes the so-called Christmas tree." Howard quips "And that, Charlie Brown, is what boredom is all about."

Penny says that she’ll put their presents under her tree. Sheldon is upset saying that Penny is not giving her a present, rather an obligation. He must give her something of equal value based upon on her present and her perceived level of friendship. Raj and Howard end up taking him to the mall.

Leonard and David are heading up the stairs helping Leonard after the motorcycle fell over on his leg. They run into Penny who is surprised that David is a and they became quickly smitten with each other. Penny claims to be a who would love to see his science lab. David proposes to take her up to dinner up the coast on his bike. Leonard is left on his own to figure out what just happened.

Sheldon's shopping does not go well in a bath & body shop which is a "cacophonous assault of, , , and ." To be fair, though, it is less scary than the shop next door. Howard picks a gift basket to purchase, but Sheldon stops him. He has no knowledge of what size gift basket to get. He experiments by "giving" the gift basket to the sales clerk. Since she acts just like Penny, Howard claims that they’ll take it.

Leonard gets a little shock in the university's cafeteria finding Penny with David and having taken his offer of looking around the labs even though he had also offered to show Penny around. David is totally into Penny, saying she has an agile mind (among other things) and he has forgotten about working with Leonard. He is more interesting in doing some research with Penny about the effects of shots on a gorgeous 22-year-old woman.

Back at the apartment, Leonard is upset and lying on the couch when Raj and Howard enter carrying several huge gift baskets. Sheldon's plan is to open Penny's gift first, then excuse himself with some "gastric trouble," and get the appropriately-priced basket, returning the others later. Howard wonders if Leonard has already gotten Penny the perfect gift; a new boyfriend.

Leonard goes over to Penny’s finding her drinking and  minus the eggnog. He demands an answer to why Penny is suddenly dating someone smarter than himself when she thought he was too smart for her, the very thing that broke them up at the beginning of the season. Penny bursts into tears wondering why he was yelling at her. Leonard immediately retreats and tries to find out what's wrong. She says that David is an idiot because he should have taken the nude photos of his wife off his cell phone before taking nude photos of his girlfriend. Leonard asked about the nude pictures to which Penny responded, “THAT'S what you got from that? The guy is married!" Penny also asks that if he is 'perfectly happy' with the way things are, then why is he jealous. Leonard apologizes and asks her to give him this one since is Christmas. They end up cuddling. She relents and wishes him a Merry Christmas. And his leg is better, thank you very much.

Later Penny brings over her Christmas presents. Sheldon gets a napkin, which when turned over was signed by Leonard Nimoy. "To Sheldon, Live Long and Prosper. Leonard Nimoy." First he is speechless and then Penny apologizes that it is dirty because he wiped his mouth on it. Sheldon then exclaims that he now has the of Leonard Nimoy and can grow  his own. Sheldon runs off. Leonard gives Penny a set of children’ science experiments because she told David she was so into science. Leonard gets some motorcycle lessons to prevent any future accidents. Sheldon returns with all of the gift baskets thinking that it still doesn't equal the value of her gift, so he gives her a hug.

Penny: Leonard, look! Sheldon's hugging me!

Leonard: It's a Saturnalia miracle!

Critics
"As a Christmas episode this definitely contains the feel good factor but more than that it is the best episode this season. Combining character development and humor in a blend which this show can do really well." - The TV Critic's Review

Quotes
Penny: Hey Sheldon, are you and Leonard putting up a Christmas tree?

Sheldon Cooper: No, because we don't celebrate the ancient pagan festival of Saturnalia.

Penny: Saturnalia?

Howard Wolowitz: Gather round, kids, it's time for Sheldon's beloved Christmas special.

Sheldon Cooper: In the pre-Christian era, as the winter solstice approached and the plants died, pagans brought evergreen boughs into their homes as an act of sympathetic magic, intended to guard the life essences of the plants until spring. This custom was later appropriated by Northern Europeans and eventually it becomes the so-called Christmas tree.

Howard Wolowitz: And that, Charlie Brown, is what boredom is all about.

Penny: Dave is not smarter than you. He's an idiot.

Leonard Hofstadter: Really? (smiling) Why would you say that?

Penny: Because a smart guy takes the nude photos of his wife off his cell phone before he tries to take nude photos of his girlfriend.

Leonard Hofstadter: He tried to take nude photos of you?

Penny: That's what you took from that?!!

Sheldon Cooper: (after opening Penny's gift) Oh... a napkin...

Penny: Turn it over.

(he does, and is so shocked that he has to grab the chair to keep from falling over)

Sheldon Cooper: "To Sheldon, live long and prosper... Leonard Nimoy."

Penny: Yeah, he came into the restaurant. Sorry the napkin's dirty. He wiped his mouth with it.

(Sheldon stands up quickly, shocked again)

Sheldon Cooper: I possess the DNA of Leonard Nimoy?!

Penny: Well... yeah, yeah, I guess. But look, he signed it!

Sheldon Cooper: (very excited) Do you realize what this means? All I need is a healthy ovum and I can grow my own Leonard Nimoy!

Penny: Okay, all I'm giving you is the napkin, Sheldon.

Penny: (after getting several gift baskets) Sheldon, what did you do?

Sheldon Cooper: (worried) I know! It's not enough, is it? Here...

(he slowly and awkwardly hugs Penny, who is completely shocked)

Penny: Leonard, look! Sheldon's hugging me!

Leonard Hofstadter: It's a Saturnalia miracle!

Trivia

 * Howard says, "Okay, he’s invited for dinner in the Bottle City of Kandor. He miniaturizes himself, enters the city where he loses his superpowers. Now, before dinner, his host says, 'who’s up for a little Kryptonian tetherball?' Superman says 'sure,' works up a sweat, comes back to Earth, his uniform now stained with indestructible Kryptonian perspiration." Sheldon suggests, "Superman would have taken his uniform to a Kandorian dry cleaner before he left the Bottle." In The Cooper-Hofstadter Polarization, Leonard revealed the following, as Penny held the DC Direct Bottle City of Kandor Prop, "You see, Kandor was the capital city of the planet Krypton, it was miniaturized by Brainiac before Krypton exploded and then rescued by Superman." Superman keeps the bottled city safe in his Fortress of Solitude.
 * Sheldon gives out one of his rare hugs for Penny.
 * David Underhill won the in 2007.
 * In claims of intellectual superiority, David Underhill is to Leonard as Dennis Kim is to Sheldon.