Sheldon: I should have brought an umbrella.
Leonard: What for? It's not gonna rain.
Sheldon: I know that, but with skin as fair as mine, moon burn is a real possibility.

Sheldon: Are you asking me or telling me?
Leonard: Telling you?

Sheldon: That's not an apology; that's simply an acknowledgment that I was right.
Leonard: Okay, I'm sorry.
Sheldon: There you go.

I assure you, you'll be sorry you wasted your money on an iPod when Microsoft comes out with theirs.

Leonard: What am I doing in your spam folder?
Sheldon: I put you there after you forwarded me a picture of a cat playing the piano entitled, "this is funny."

Sheldon: Roommates agree that Friday nights shall be reserved for watching Joss Whedon's brilliant new series, "Firefly."
Leonard: Does that really need to be in the agreement?
Sheldon: Might as well settle it now; it's going to be on for years.

Wheaton: Embrace the Dark Side!
Sheldon: That's not even from your franchise!

Can I get you something? A feminine hygiene product or a bowel-regulating yogurt?

Dr. Plimpton, Penny is a waitress who doesn't understand the role gasoline plays in the internal combustion engine.

Leonard: Well, it wasn't my fault.
Sheldon: The implication being that you somehow tripped and fell into her lady parts?

Dr. Plimpton: What if there's a disaster that destroys all of the USB ports?
Sheldon: Then there's really no reason to live, is there?

Leonard: I think any university would want you -- except, of course, any university that had already had you, because they would have already wanted you, before they, you know, got you.
Sheldon: From the mind that brought you "hi-lo."

TBBT Quotes

Oh, Bernadette, please play my clarinet.

Raj's poem

Sheldon: I'll have a diet Coke.
Penny: Can you please order a cocktail? I need to practice mixing drinks.
Sheldon: Fine... I'll have a virgin Cuba Libre.
Penny: That's... rum and Coke without the rum.
Sheldon: Yes, and would you make it diet?