Leonard: "Upon review, I've changed my mind about the Cooper-Hofstadter hypothesis that space-time is like a super-fluid. In fact, it's inspired me to come up with my own theory. Maybe space-time is like two clowns with their heads in a bucket. Much like Cooper and Hofstadter."

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: 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: 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.

Sheldon: I like it. I think you're on to something.
Leonard: Really? You're not messing with me?
Sheldon: Not at all. In fact, I have got something for just such an occasion. I was starting to think I'd never get a chance to give it to you. Good job!
Leonard: You're giving me a sticker?
Sheldon: Not just a sticker. That's a sticker of a kitty saying "Mee-wow".
Leonard: I'm not a preschooler.
Sheldon: Fine, I'll take it back.
Leonard: I earned this. Back off.

Sheldon: Can I respond now?
Leonard: Do it.
Sheldon: You mess with the bull, you get the horns. I'm about to show this guy just how horny I can be.
Leonard: Somebody else do it.

Bernadette: (In pageant video) And you should pick me for Miss. California Quiznos 1999, because I want to tell you what I want, what I really really want. I'll tell you what I want, what I really really want. I wanna. I wanna. I wanna. I wanna, really, really, be the California Quiznos 1999.