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.

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.

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: 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?