Episode 1: Pilot
Original Air Date: 24 September 2007
A pair of brilliant theoretical physicists meet a woman who shows them how little they know about the real world.

Episode 2: The Big Bran Hypothesis
Original Air Date: 1 October 2007
Penny is furious and more than a little freaked out with Leonard and Sheldon when they sneak into her apartment overnight, and clean it while she is sleeping.

Episode 3: The Fuzzy Boots Corollary
Original Air Date: 8 October 2007
Leonard gets upset when he discovers that Penny is seeing a new guy, so he tries to trick her into going on a date with him.

Episode 4: The Luminous Fish Effect
Original Air Date: 15 October 2007
Sheldon's Christian-fundamentalist mother visits to get him out of the funk he's in after he is fired for being disrespectful toward his new boss.

Episode 5: The Hamburger Postulate
Original Air Date: 22 October 2007
Leonard and his colleague Leslie spend the night together. But Leslie tells Leonard after the fact that she's only interested in a one-night stand.

Episode 6: The Middle Earth Paradigm
Original Air Date: 29 October 2007
The guys are invited to Penny's Halloween costume party. During the party, Leonard has a run-in with Penny's ex-boyfriend.

Episode 7: The Dumpling Paradox
Original Air Date: 5 November 2007
When Howard hooks up with Penny's old friend, it ruins the nights on which all of the guys play the game \"Halo.\"

Episode 8: The Grasshopper Experiment
Original Air Date: 12 November 2007
Rajnesh's parents, communicating from India by Web cam, arrange for him to go out with another Indian woman in the hopes of marriage, but his date turns out to have more in common with Sheldon.

Episode 9: The Cooper-Hofstadter Polarization
Original Air Date: 17 March 2008
Leonard and Sheldon's friendship is put to the test when Leonard wants to present a paper they co-authored at a physics convention, but Sheldon does not.

Episode 10: The Loobenfeld Decay
Original Air Date: 24 March 2008
Leonard lies to Penny so that he and Sheldon can get out of watching her perform. However, Sheldon believes that the lie has too many loose ends, so he comes up with a new, unnecessarily complex one to replace it.

Episode 11: The Pancake Batter Anomaly
Original Air Date: 31 March 2008
Sheldon is sick, and Leonard and the guys sneak out to a \"Planet of the Apes\" movie marathon to get out of taking care of him--which leaves Penny as the only person to whom the needy Sheldon can turn.

Episode 12: The Jerusalem Duality
Original Air Date: 14 April 2008
Sheldon is threatened when a new 15-year-old prodigy who is smarter than him joins the lab, so the guys come up with a plan to get rid of him.

Episode 13: The Bat Jar Conjecture
Original Air Date: 21 April 2008
Sheldon becomes so intent on demonstrating his intellectual superiority over his Physics Bowl teammates that they boot him, and replace him with his nemesis.

Episode 14: The Nerdvana Annihilation
Original Air Date: 28 April 2008
Penny gets mad at Leonard because the guys' new \"time machine\" causes her to miss work. Leonard is so devastated that he vows to give up all of his nerd memorabilia.

Episode 15: The Shiksa Indeterminacy
Original Air Date: 5 May 2008
Sheldon's sexy twin sister arrives in town from Texas, and all of Sheldon's friends fight over who will get to be with her.

Episode 16: The Peanut Reaction
Original Air Date: 12 May 2008
When Penny and the guys learn that Leonard has never had a birthday party, they decide to try and throw a surprise party for them.

Episode 17: The Tangerine Factor
Original Air Date: 19 May 2008
After Penny breaks up with her new guy, she agrees to go out on a date with Leonard. However, both of them have reservations about the date soon after agreeing to it.