Sheldon: Couples costumes are one of the few benefits of being in a relationship. Now imagine this, you and I entering Stuart's party and all eyes turn to see America's most beloved and glamorous couple.
Amy: Yeah?
Sheldon: R2-D2 and C-3PO. Dibs on 3PO.

Sheldon: How about one of the most beguiling and influential couples of the 20th century? Hewlett and Packard. Dibs on Hewlett.
What? You want to be Hewlett?

Sheldon: A Tardis makes no sense. It's a time machine from a science-fiction show. it has nothing to do with Halloween. That being said, if you don't get a Tardis, you stink and your party stinks.

Amy: There are certain things that say to the world, I have a boyfriend and he's not made up. Matching cotumes, hickeys and sex tapes. Pick one.
Sheldon: What's a hickey?

Amy: Sheldon, when I said couples costume, I meant like Romeo and Juliet or Cinderella and Prince Charming, not two robots from some silly movie I don't even like.
Sheldon: Okay, I'm gonna let that slide because I know you're hopped up on tea bags.

Amy: How about Raggedy Ann and Andy? I loved them growing up.
Sheldon: No, I don't think so. Those dolls represent three things I do not care for: clowns, children and raggedness. I think it's a lost cause.

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.

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.

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

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.

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.

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.

Amy: Why don't we do something athletic like go over to the university pool and play water polo?
Leonard: No good, Sheldon doesn't float.
Sheldon: That is true. I have a higher than normal bone density. If I run too deep a bath, I drown.