This is a timeline of events that occured during the first season or approximately September, 2007 to May, 2008.
TIMELINE
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1. “Pilot”
September 1, 2007 Penny moves in and meets Sheldon and Leonard, for whom it is love at first sight. Sheldon & Leonard fail to get Penny’s TV from Kurt, her ex-boyfriend
2.. “The Big Bran Hypothesis”
September 3, 2007 Penny asks Leonard to sign for some furniture she’s having delivered
September 4, 2007 The furniture arrives. Leonard and Sheldon get it upstairs with difficulty, due to the non-functional elevator. Sheldon is so upset by Penny’s messy apartment that he returns later that night to tidy up
September 5, 2007 Penny discovers the boys were in her apartment while she was asleep and is furious, but she does later forgive them
September 6, 2007 Leonard, Sheldon, Raj and Howard try to assemble Penny’s furniture
3. “The Fuzzy Boots Corollary”
September 10, 2007 When Leonard sees Penny kissing Doug, he is devastated.
September 11, 2007 Leonard asks out Leslie Winkle, who says no
September 12, 2007 Leonard and Penny go on a “date”
4. “The Luminous Fish effect”
September 19, 2007 At a party to welcome Dr. Gablehouser, the new head of the Cal Tech physics department, Sheldon is fired
September 20, 2007 Sheldon and Penny go to the grocery store
October 11, 2007 Sheldon’s mom arrives
October 12, 2007 Sheldon apologizes to Dr. Gablehouser and is rehired
5. “The Hamburger Postulate”
October 14, 2007 Leslie Winkle approaches the group at the Cheesecake Factory
Tuesday, October 16, 2007 Leonard & Leslie play in string quartet, then hook up
October 17, 2007 Leslie dumps Leonard
October 18, 2007 Sheldon & Leonard eat at the Cheesecake factory
6. “The Middle Earth Paradigm”
Sunday October 21, 2007 after losing at paintball the boys are invited to Penny’s Halloween party
Saturday October 27, 2007 at Penny’s Halloween party Kurt shows up. Penny kisses Leonard
7. “The Dumpling Paradox”
Friday November 2, 2007 Penny’s friend Christy arrives on Halo Night and launches into a sexual relationship with Howard
Saturday November 3, 2007 – Christy moves in with Howard
November 6, 2007 Sheldon, Leonard & Raj eat at Szechwan Palace
Wednesday, November 7, 2007 on Halo night Christy leaves
8. “The Grasshopper Experiment”
November 8, 2007 Raj’s parents tell him about Lalita Gupta
November 9, 2007 A date set up between Raj & Lalita. Raj learns he can talk to girls if he is drunk
Saturday November 10, 2007 Raj & Lalita’s date, she leaves with Sheldon
November 11, 2007 Sheldon sings at the Cheesecake Factory
August, 2007 to August, 2008 a box at UPS falls on Eric’s head [The Locomotive Manipulation]
9. “The Cooper-Hofstader Polarization”
March 17, 2008 Leonard learns he’s been invited to speak about supersolids at Bose- Einstein Condensates conference
March 18, 2008 Penny selects Leonard’s wardrobe
March 18, 2008 Penny forwards to Sheldon a LOL Cat e-mail [the Panty Piñata Polarization]
March 19, 2008 Leonard gives speech, but Sheldon shows up
March 20, 2008 Howard controls some lights in China
10. “The Loobenfeld Decay”
March 24, 2008 Sheldon and Leonard are invited to see Penny in “Rent”
March 25, 2008 Sheldon fabricates an elaborate lie why they can’t go
Friday March 28, 2008 “Rent” is performed
March 29, 2008 Sheldon worries the lie might not hold up
March 30, 2008 “Leo” shows up for his “intervention”
11. “The Pancake Batter Anomaly”
March 31, 2008 Penny returns from a trip to Nebraska
Sunday April 6, 2008 Sheldon is sick
April, 2008 Penny last has sex for six months [The Barbarian Sublimation]
12. “The Jerusalem Duality”
April 14, 2008 the boys meet Dennis Kim
April 15, 2008 Sheldon visits Howard and Raj to find a new job
April 16, 2008 at the reception Dennis shows up with a girl
April 17, 2008 the boys see Dennis in the park with the girl
13. “The Bat-Jar Conjecture”
April 21, 2008 the boys decide to enter the physics bowl
Saturday April 26, 2008 they discuss team names, but after a practice round Sheldon is kicked off the team
April 28, 2008 Leonard, Raj and Howard draft Leslie Winkle for their team
April 29, 2008 The physics bowl, Sheldon loses
April 30, 2008 Leonard taunts Sheldon about his loss
14. “The Nerdvana Annihilation”
May 2, 2008 Leonard buys a time machine
May 3, 2008 the time machine arrives. Penny is late for work and blames the boys playing with toys.
May 4, 2008 Leonard wants to get rid of all his collectibles
May 7, 2008 Sheldon tells Leonard he has an eidetic memory [The Creepy Candy Coating Corollary]
15. “The Pork Chop Indeterminacy”
May 8, 2008 Missy Cooper arrives and all the boys try to hit on her, but none succeed
May 9, 2008 Missy leaves for Texas
16. “The Peanut Reaction”
May 12, 2008 the gang discuss birthdays
My 13, 2008 Penny blackmails Sheldon into having a birthday party for Leonard
May 17, 2008 Leonard’s birthday party that he misses
17. “The Tangerine Factor”
May 19, 2008 Leonard asks Penny out on a date
May 24, 2008 both Leonard and Penny talk to Sheldon then leave on their date