"The Gothowitz Deviation"

Howard takes Raj with him to the Goth dating scene; Sheldon uses chocolate as part of his behavioral experiment on Penny.

"The Jiminy Conjecture"

Leonard and Penny try and make things not awkward after their hookup; Sheldon and Wolowitz bet their best comic books on a bet to determine the species of a cricket

"The Electric Can Opener Fluctuation"

Sheldon runs to his mother when he learns the gang messed with her arctice expedition's data; the guys go chasing after him with Leonard sacrificing his chance with Penny.

"The Monopolar Expedition"

When Sheldon gets news he's going to the North Pole on a NSF expedition, he invites the guys as his group.

"The Classified Materials Turbulence"

Howard enlists the help of the boys in order to fix his space toilet. Stuart and Penny go on their second date.

"The Vegas Renormalization"

When Wolowitz gets dumped by Leslie, Raj and Leonard take him to Las Vegas to get over his breakup. Meanwhile, Sheldon gets locked out of the apartment and has to crash at Penny's.

"The Hofstadter Isotope"

A friend of the guys who works at the comic book store, Stuart (Kevin Sussman) hits it off with Penny, prompting Leonard and Wolowitz to head out to ladies' night at a local bar.

"The Dead Hooker Juxtaposition"

Penny gets jealous of the guys' new sexy female neighbor (Valerie Azlynn)

"The Work Song Nanocluster"

The boys help Penny with her new business selling Penny Blossoms.

"The Terminator Decoupling"

On a train ride to San Francisco, Leonard, Sheldon, Wolowitz, and Raj discover that Summer Glau is on their train ride.

TBBT Quotes

Sheldon: Are you still mad about the sperm bank?
Leonard: No!
Sheldon: Do you want to hear an interesting thing about stairs?
Leonard: Not really.
Sheldon: If the height of a single step is off by as little as two millimeters most people will trip.
Leonard: I don't care—two millimeters?! That doesn't seem right.
Sheldon: No, it's true! I did a series of experiments when I was twelve; my father broke his clavicle.

Penny, there's only one cookie with something in the middle that solves life's problems, and that's an Oreo. Or a Nutter Butter, if you're in a pinch.

Sheldon