Sheldon: I got a splinter.
Amy: What do you want me to do about it?
Sheldon: Relationship Agreement - Section 4: Boo-boos and Ouchies. You have to take care of it.
Amy: I should've gotten a lawyer.

Amy: Sheldon I'm disappointed, as a brilliant man you're entitled to a vice. I could understand frequenting an opium den or hunting your fellow man for sport, but this? Lame-o!
Sheldon: Well, A, comic books employ story telling through sequential art, a medium that dates back 17, 000 years to the cave paintings of Lascaux, and B, you play the harp. Like that's cool.

Amy: (Reading Sheldon's relationship agreement) Section 5, Hand Holding: Hand holding is only allowed under the following circumstances: A. either party is in danger of falling of a cliff, precipice or ledge; B. either party is deserving of a hearty hand shake after winning a Nobel prize; C. moral support during flu shots.

Amy: How did you get into my apartment?
Sheldon: Wow. Is that the kind of nagging I can expect now that you're my girlfriend?

Sheldon: I present to you the Relationship Agreement. A binding covenant that in its 31 pages enumerates, illuminates and codifies the responsibilities of Sheldon Lee Cooper - hereinafter referred to as the "Boyfriend" - and Amy Farrah Fowler - hereinafter referred to as the "Girlfriend.
Amy: That's so romantic!
Sheldon: Mutual indemnification always is.

Sheldon: (knock, knock, knock) Penny!
(knock, knock, knock) Amy!
(knock, knock, knock) Bernadette!

Stuart: I'll ring it up. It's like shooting nerds in a barrel.

Howard: I thought you didn't like Facebook any more.
Sheldon: Don't be silly, I'm a fan of anything that tries to replace actual human contact.

Amy: If you're keeping him, I've got a cage you can borrow. One of the test monkeys slipped on a banana peel and broke his neck. It was both tragic and hysterical.

Sheldon: Trust me, if I had a death ray I wouldn't be living here. I'd be in my lair enjoying the money the people of Earth gave me for not using my death ray.

Leonard: I'm going to the movies with Penny. I don't want her to think I think it's a date.
Sheldon: Do you think it's a date?
Leonard: No, but she might think I think it's a date even though I don't.
Sheldon: Or you might think she thinks you think it's a date even though she doesn't.
Leonard: Are we over thinking this?
Sheldon: Not at all.

Leonard: Star Wars on Blu-ray.
Penny: Haven't you seen that movie like a thousand times?
Leonard: Not on Blu-ray. Only twice on Blu-ray.
Penny: Oh, Leonard.
Leonard: I know, it's high resolution sadness.

Penny: And remember, he's more afraid of you than you are of him.
Sheldon: That doesn't help.
Penny: No, I was talking to the bird.

Leonard: Too casual?
Sheldon: For an audience with the queen, yes. For an evening of passing a bottle of fortified wine around a flaming trash can, you look great.

(Leonard is pointing out the monotonous movie habits of their former relationship.)
Leonard: No. You always picked, and it was always the same. An hour and a half of beach houses in the rain until the woman turns around and realizes love was here all along.
Penny: But, come on, that is a great movie, and it starts in ten minutes.