Leonard: Are you sure?
Penny: Well, have you slept with her yet? ... You dog! Good for you.
Leonard: Does that change things?
Penny: No.
Leonard: So why'd you ask?
Penny: I'm nosy. See ya.

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

Penny: I mean, who even reads Scientific American?
Leonard: It's kind of a big deal.
Penny: If it's such a big deal, how come the biggest celebrity they could get for the cover is a molecule?

Howard: I'm not signing a prenup.
Penny: All right, Howard Wolowitz, listen up! You sign anything she puts in front of you, because you are the luckiest man alive. If you let her go, there is no way you can find anyone else. Speaking on behalf of all women, it is not going to happen, we had a meeting.

Sheldon: Scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and as it always has, rock crushes scissors.

Mrs. Wolowitz Tell her we're going to the Olive Garden. I have a coupon from the paper.
Howard: We're not going to the Olive Garden, ma!
Mrs. Wolowitz Oh, Mr. Big Shot with his Red Lobster.

Stephanie: So, how was your day?
Leonard: You know, I'm a physicist, I thought about stuff.
Stephanie: That's it?
Leonard: I wrote some of it down.