Penny: There's the little family!
Raj: Hello.
Stuart: Hello.
Leonard: And their Sherpas.

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: 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.

Amy: Well, uh, Howard and Bernadette had their baby.
Mary Cooper: (gasps) Oh, that's wonderful! Now, have they decided to raise it Jewish or regular?
Sheldon: Welcome to Texas.

Bernadette: Everyone's a better mom than me.
Raj: Oh, don't take it so personally, maybe your baby's just a jerk.

Mary Cooper: Sheldon, if you're trying to prove me wrong, the tighty-whities on your head ain't changing my mind.