"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.

"The Cushion Saturation"

A paintball game leads to a fight between Penny and Sheldon, but also for a romance between Wolowitz and Leslie!

"The Maternal Capacitance"

Leonard's mother, Mrs. Hofstadter (Christine Branksi) comes into town and she ends up being exactly like Sheldon.

TBBT Quotes

Penny: Here's a question-- as an alien pretending to be human, are you planning to engage in any post-prom mating rituals with Amy?
Sheldon: There are post-prom mating rituals?
Penny: Not always. Unless your date drives a van with an air mattress, then always.
Sheldon: Well, if it's part of the prom experience, then I'm open to it.
Penny: You're kidding.
Sheldon: I may be an alien, but I have urges.If Amy wants to copulate by firing her eggs into space, well, then, I will happily catch them with the reproductive sac on my upper flermin. I'm not the best at reading facial cues, but I can see that you're a little turned on.

Sheldon: Why do you have the Chinese character for "soup" tattooed on your right buttock?
Penny: It's not "soup," it's "courage."
Sheldon: No it isn't. But I suppose it does take courage to demonstrate that kind of commitment to soup.
Penny: How'd you see it? You said you wouldn't look.
Sheldon: Sorry. As I told you, the hero always peeks.