Penny: I always tear up when the Grinch's heart grows three sizes.
Sheldon: Tears seem appropriate. Enlargement of the heart muscle, or hypertrophic cardiomyopathy, is a serious disease which can lead to congestive heart failure.

That's all I know. Oh, wait! Fig Newtons were named after a town in Massachusetts, not the scientist.

Penny

Penny: Is that why they're called Fig Newtons?
Sheldon: No. Fig Newtons are named after a small town in Massachusetts. No, don't write that down!

Senior fitness was canceled; it turns out you can forget how to ride a bike.

Mrs. Wolowitz

It's not enough you get the prom queen, you have to get the head of the decorating committee, too?

Wolowitz

Can't you surprise him in some other way? For example, I bet he'd be delightfully taken aback if you cleaned your apartment.

Sheldon

While I appreciate the "oh, snap," I'm uncomfortable having your moist breath in my ear.

Sheldon [to Raj]

If I hadn't gone into microbiology, I would have gone into physics. Or ice dancing.

Bernadette

Sheldon: Why are you crying?
Penny: Because I'm stupid!
Sheldon: Well that's no reason to cry; one cries because one is sad. For example, I cry because others are stupid and it makes me sad.

Sheldon: Where's your notebook?
Penny: I don't have one.
Sheldon: How are you gonna take notes without a notebook?
Penny: I have to take notes?
Sheldon: How else are you gonna study for the tests?
Penny: There's gonna be a test?
Sheldon: Tests. Here, it's college ruled, I hope that's not too intimidating.

Leonard: The more the merrier.
Sheldon: That's a false equivalency, more does not equal merry. If there were two thousand people in this apartment, would we be celebrating? No, we'd be suffocating.

Sheldon, you remind me of a young Lex Luthor.

Raj

The Big Bang Theory Season 3 Quotes

Wolowitz: Sheldon. You remember the first few weeks; we were looking for magnetic monopoles and not finding anything, and you were acting like an obnoxious, giant dictator?
Raj: I thought we were going to be gentle with him.
Wolowitz: That's why I added the "tator"

Wolowitz [after seeing Penny jump Leonard]: Damnit, I should have gone over and said we were back
Raj: Yeah, it was "first come, first serve."