Penny: You're having a bad dream.
Leonard: Oh, thank God. I was eating my friends. Well, one friend and one acquaintance.
You know what, Bert's okay. Two friends.

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.

Stuart: Whoa, whoa. You're not gonna cut open a meteor, are you? Have you not learned anything from comic books? Space viruses? Pod people? I sell nothing but warnings.

Bert: I don't really have dreams, when I sleep or in life.

Howard: And then Andy said if we want privacy, we should plant some trees. The only way I know how to do that is to give a dollar and tree shows up in Israel.