Penny: David is not smarter than you, because a smart man would take the naked pictures of his wife off his phone before trying to take naked pictures of his girlfriend!
Leonard: He tried to take nude photos of you?
Penny: That's what you took from that?! The guy is married!
Leonard: Oh, that's terrible.
Penny: And you, if you're so fine with how the way things are between us then why are you so jealous?
Leonard: The important thing is he's married and that's terrible.
Penny: Nice save, genius.

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: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Sheldon: All I need is a healthy ovum and I can grow my own Leonard Nimoy.
Penny: Okay, all I'm giving you is the napkin, Sheldon.

Penny: Now, honey, it's okay. You don't have to get me anything in return.
Sheldon: Of course I do. The essence of the custom is that I now have to go out and purchase for you a gift of commensurate value and representing the same perceived level of friendship as that represented by the gift you've given me. It's no wonder suicide rates skyrocket this time of year.
Penny: Okay, you know what? Forget it. I'm not giving you a present.
Sheldon: No, it's too late. I see it. That elf sticker says to Sheldon. The die has been cast, the moving finger has writ, Hannibal has crossed the Alps.

Sheldon: If I would give you this gift basket, based on that action alone and no other data, infer and describe the hypothetical relationship that exist between us.
Store Clerk: Excuse me?
Sheldon: Here. Now, are we friends? Colleagues? Lovers? Are you my grandmother?
Store Clerk: I don't understand what you're talking about and you're making me a little uncomfortable.
Howard: See? Sounds just like you and Penny. We'll take it.