Penny: I just want to know why a five-year-old boy puts on his mom's make-up and wears balloon boobies.
Leonard: They weren't boobies, they were muscles. And the make-up was green, I was pretending to be The Hulk.
Penny: You were wearing her bra.
Leonard: That was to keep my muscles from sagging. Can we please stop talking about this?!

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?

Raj: In the last hour 162 people have read our profiles. How many of them have sent us messages?
Stuart: Combined?
Raj: Yes.
Stuart: Zero.

Sheldon: You've spent time with Amy, can you think of anything she's fond of that has a bunch of flaws she hasn't noticed?
Leonard: ... I got to go.

Sheldon: Amy ruined Raiders of the Lost Ark for me, so I'm trying to find something beloved of hers and ruin that.
Howard: Because her life wasn't enough?