Leonard: Oh, I forgot about this (sweater). My aunt made it for me when I finished college.
Penny: Aww, did she hate you?
Leonard: Why because I got an ugly, itchy sweater and my brother got a car? No, I was her favorite!

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.

Leonard: If I take it off, Sheldon wins.
Penny: Sweetie, every night you don't kill him in his sleep, he wins.

Penny: If you guys were hungry, why didn't you order something at the restaurant?
Bernadette: We did. You never brought it.
Penny: Oh, that's right. Nachos and a turkey club.
Amy: Not even close.
Penny: Well, I was too busy standing up for my friend to worry about your ... I want to say salmon.
Amy: You want to say sorry.

Howard: So you can never take it (the sweater) off?
Leonard: No.
Raj: Not even to sleep?
Leonard: No.
Howard: So you're just an idiot?
Leonard: It's called proving a point.
Howard: Is the point you're an idiot?