Howard: Wow. I wonder what that guy could've done to make Sheldon not talk to him for 20 years.
Leonard: I wonder if it'd work a second time.

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.

Amy: I tried to ask him about it, and he invoked section three, article five of the marriage contract: beeswax, none of your.

Bernadette: Look, I think that's LeBron over there.
Penny: James?
Bernadette: No, LeBron Kershenbaum.

Amy: Who's Tam?
Sheldon: He was my best friend in the whole world growing up.
Amy: Really? Why have I never heard you mention him before?
Sheldon: Oh, of course I have. I'm sure I've mentioned him, like, five times this week.
Amy: I don't think you have.
Sheldon: Tam! Tam! Tam! Tam! Tam! There, it's only Thursday.
Amy: I didn't just drink the crazy milk, I bought the crazy cow.