Amy: All right, let's keep it simple. How about darts?
Sheldon: No, that's not fair either.
Penny: Why not?
Sheldon: Darts is a bar game. You've been frequenting drinking establishments since you were of legal age.
Leonard: Yeah, that's when it started.

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.

Howard: Wow, so you guys are like buds now?
Raj: Oh, yeah, we hang out all the time.
Stuart: Plus, he doesn't have a girlfriend, I don't have a girlfriend.
Raj: It's like we both had these holes in our lives, but now we fill each other's holes.
Stuart: That sounds a little funny to an American ear.
Raj: Which part?
Stuart: Just all of it.

Amy: We could go to the cadaver lab at UCLA and play real-life Operation.
Leonard: Uh-uh.
Sheldon: No.
Penny: I don't think so.
Amy: Are you sure? I mean, the nose doesn't light up, but if the corpse is fresh enough, sometimes you can get the leg to jerk.

Penny: You're unbelievable.
Sheldon: I know.