Leonard: So, how'd you two guys meet?
Zack: My company designs the menus for the Cheesecake Factory.
Leonard: Your company?
Zack: Well, it's my dad's, but me and my sister are VPs.
Leonard: So, menus?
Zack: I know it sounds easy but there's a lot of science that goes in designing them.

Zack: Cool, it's gonna be in 3-D!

Sheldon: I should've brought an umbrella.
Leonard: What for? It's not going to rain.
Sheldon: I know that, but with skin as fair as mine, moon burn is a real possibility.
Howard: That's a bazinga, right?
Sheldon: One of my best, don't you think?

Sheldon: As a native Texan, I must say I've never heard the phrase "yeeehaw" used in quite that context.

Howard: *Noticing Raj peeking through someone's window using the telescope* Oh, Raj, no. Billions of dollars have gone into inventing the Internet and filling it with pictures of naked women, so we don't have to peep through windows.

Sheldon: Hello, Amy Farrah Fowler. I'm sorry to inform you that you've been taken in by unsupportable mathematics designed to prey upon the gullible and the lonely. Additionally, I am being blackmailed with a hidden dirty sock.
Amy: If that was slang, I'm unfamiliar with it. If it was literal, I share your aversion to soiled hosiery.

Leonard: Relax, it's just a dirty sock.
Sheldon: How on earth can you say "dirty sock" and "relax" in the same sentence?

Raj: The Good Wife is on. I tell you, this is my new Grey's Anatomy.

(Sheldon notices Penny taking Leonard to his bedroom)
Sheldon: What's going on?
Penny: Get your noise-cancelling headphones, 'cause it's gonna get loud.
Sheldon: Oh, not this again.

Zack: Hey, I want to see this laser thing.
Penny: Oh, but what about the party?
Zack: It's a surprise party, doesn't matter when we get there.

Wolowitz: Good God, what have we done?

Amy: You should also know that all physical contact, up to and including coitus, is off the table.
Sheldon: May I buy you a beverage?
Amy: Tepid water please.
Wolowitz: My God, what have we done?

Zack: How can you bounce a laser off the moon if there's no gravity?

Penny: Damn you, you rat bastard! In the olden days, I never would have known he was that stupid.

Leonard: Think about what this represents. The fact that we can do this is the only way of definitively proving that there are man-made objects on the moon, put there by a member of a species that only 60 years before had just invented the airplane.
Zack: What species is that?