Sheldon: I suppose you're wondering why I put you through all this.
Leonard: You mean the last two minutes or the last 20 years?

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.

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

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: Hey, Denise. Is Stuart here?
Denise: Oh, no. Doctor's appointment.
Bernadette: Oh, is he okay?
Denise: Not since I've known him.

Sheldon: Oh, hey, Leonard. Is the podcast too loud
Leonard: I didn't hear a podcast.
Amy: I told you no one could hear it.
Sheldon: Well, I heard Ira Glass, so he's either in your earbuds or clinging to the ceiling like a gecko.

Sheldon: You know we're almost finished with our paper; we just need help tracking down the citations.
Leonard: That's busywork. Can't you just get a grad student to do it?
Amy: No, this paper is incredibly important to us, and we need someone we can trust.
Please, it would mean a lot.
Leonard: You know what? Sure. The three of us in the library looking up old papers, that actually could be kind of fun.
Sheldon: Oh, no, we won't be there.
Leonard: It just got more fun.