Wolowitz: If I die, promise me you'll never have sex with another man.

Stuart: Hey. Hey, look at you guys!
Amy: I'm Raggedy Ann, and he's Raggedy C-3PO.
Sheldon: It was a compromise. I lost.

Penny: Okay, glasses off. Find Waldo.

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.

Sheldon: All games are made up. They're not found in nature. You don't just dig in the ground, and come across a rich vein of Rock'em Sock'em Robots.

Sheldon: The word is Polish. See, look.
Polish sausage. And the model of the solar system developed by Nicolaus Copernicus, a Polish astronomer. And then, finally, if that wasn't enough, which it should've been, this is Madame Curie killing herself by discovering radium, who, although she was a naturalized French citizen, was Polish by birth.
Penny: Excuse me, the word is polish. See? Small p.
Sheldon: Ah! So it is. I guess we both share blame on this one.

Leonard: In what universe is that a present?
Sheldon: It's not a present, it's the present. Look. There's you and me. It's Penny and Amy. We're playing Pictionary. In the present.
Penny: Oh, my God, we're gonna kill them.

Penny: Once again, unbelievable.
Sheldon: Yeah, once again, I know.

Sheldon: You know, I am very disappointed that I won't be able to celebrate Howard's accomplishment tonight.
Amy: Me, too. But we'll see him tomorrow.
Sheldon: Yes, it's just that in all the years I've known him, he's never had the opportunity to receive my admiration. I was excited to see the look on his face when it finally happened.

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

Crowd at the airport: There he is! Howie! Howie!
Wolowitz: Whoa, thank you. Great to be back on Earth.
Howie Mandel: Uh, I think they're here for me, Ringo.

Sheldon: Yeah, you had a good run, fake Wolowitz. We'll remember you with nostalgic fondness. The way we do the dial-up modem, the VHS tape, or Leonard's gym membership.

Leonard: I don't have a problem with Stuart. Besides, he gives us a 20% discount at his comic book store.
Sheldon: Well, I don't sell my friendship that cheaply.
Stuart: I can go 30.
Sheldon: Welcome aboard, old chum.

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.

Leonard: If you want help, just hire a grad student.
Penny: Maybe I could do it.
Sheldon: You, really? You can assess the quality of my work? Okay, um, here. I wrote this when I was five years old.
Penny: A proof that algebraic topology can never have a non self-contradictory set of abelion groups. Im just a blond monkey to you, aren't I?
Sheldon: You said it, not me.