"The Cooper-Hofstadter Polarization"

After cleaning up after an internet experiment, Leonard discovers a letter in the trash can inviting the roommates to present some research they've done to a physics conference.

"The Grasshopper Experiment"

Raj is scared when his parents arrange a blind date for him with a girl from his childhood as he's still unable to women. Penny takes up bar tending to make some extra money.

"The Dumpling Paradox"

Penny's slutty friend, Chrissy (Brooke D'Orsay) from Nebraska, is in town and is seduced by Wolowitz. The pair ends up taking over Penny's apartment, forcing her to sleep on Leonard and Sheldon's couch.

"The Middle-Earth Paradigm"

The guys are invited to Penny's Halloween party and decide to go only when the idea of costumes are mentioned. At the party, Wolowitz and Leonard attempt to socialize until Penny's ex, Kurt, shows up and humiliates Leonard.

"The Hamburger Postulate"

While eating at the Cheesecake Factory where Penny works, the guys run into Leslie Winkle, the girl who previously rejected Leonard. Leslie asks Leonard to play in her string quartet as the cellist, but what she really wants is him.

"The Luminous Fish Effect"

Sheldon is fired from his job at Caltech when he insults his boss Dr. Eric Gablehauser. Unemployed, Sheldon quickly spirals into depressions which Leonard tries to end by bringing over Sheldon's mother.

"The Fuzzy Boots Corollary"

When Leonard witnesses Penny kissing a guy in front of their apartment, he is hurt and feels "rejected." The guys try to convince him to ask a girl out at work and when he's rejected by Leslie Winkle, he is even more depressed.

"The Big Bran Hypothesis"

When Sheldon and Leonard head over to Penny's apartment to drop off a package that arrived for her, Sheldon is bothered by how messy her apartment is.

In the pilot, life is about to change for two geniuses, Sheldon and Leonard when the beautiful Penny moves in across the hall. Leonard sees potential love interest in Penny and offers to retrieve her television from her ex-boyfriend.

TBBT Quotes

Oh, Bernadette, please play my clarinet.

Raj's poem

Sheldon: I'll have a diet Coke.
Penny: Can you please order a cocktail? I need to practice mixing drinks.
Sheldon: Fine... I'll have a virgin Cuba Libre.
Penny: That's... rum and Coke without the rum.
Sheldon: Yes, and would you make it diet?