Leonard: Where have you been?
Sheldon: Oh, Leonard, if I was prone to sarcasm I'd say I was pulling off a major heist at the museum of laundry baskets.
Leonard: (Counts to 10 and takes a breath) What I meant was, gee Sheldon! You were gone a long time!

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

Leonard: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Bernadette: I told you you shouldn't have espresso after dinner. I know the little cups make you feel big but it's not worth it.

Bernadette: You can't just throw everything in the closet.
Howard: Hey, you can tell me what to do and how to do it, but not both at the same time. This isn't sex.

Sheldon: What can I do for you ladies?
Amy: You have something we want.
Sheldon: Oh, dear. My mother warned me this is what happens to pretty boys in the big city.
Penny: No, we just want information.
Sheldon: Oh. I've got that spades. Ravage me.