Howard: Grab a napkin, homey, you just got served.
Leonard: That's fine, you win.
Howard: What's his problem?
Sheldon: His imaginary girlfriend broke up with him.
Howard: Been there!

Sheldon: Leonard, I don't think I can do this.
Leonard: What are you, kidding? You're a semi-pro.
Sheldon: No, we are committing genetic fraud. There's no guarantee that our sperm's going to generate high-IQ offspring. Think about that. I have a sister with the same basic DNA mix who hostesses at Fuddruckers.

Penny: And what kind of doctor removes shoes from asses?

Sheldon: I read an article about Japanese scientists who inserted DNA from luminous jelly fish into other animals; and I thought "Hey! Fish night-lights".
Leonard: Fish night-lights.
Sheldon: It's a billion dollar idea, ssh!

Penny: It is the things you love that make you who you are.
Wolowitz: I guess that makes me large breasts.

Sheldon: I do feel obligated to point out to you that she did not reject you, you did not ask her out.
Leonard: You're right. I didn't ask her out. I should ask her out.
Sheldon: No! No that was not my point. My point was don't buy a cat.
Leonard: No, but you're right, I should march over there and ask her out.
Sheldon: Oh, goody! We're getting a cat.

Sheldon: Engineering. Where the noble semiskilled laborers execute the vision of those who think and dream. Hello, Oompa-Loompas of science.

Penny: I'm a vegetarian, except for fish, and the occasional steak. I LOVE steak!
Sheldon: Well, that's interesting. Leonard can't process corn.

Mary Cooper: Honey, why did you get a loom?
Sheldon: Well, I was working with luminous fish and I thought, hey, loom.

Penny: Would it be weird if I used your shower?
Leonard: No.
Sheldon: Yes.
Leonard: (to Sheldon) No!
Sheldon: No?
Leonard: No!
Sheldon: (to Penny) No.

Leslie: There's no reason to feel uncomfortable just because we've seen each other's faces and naked bodies contorted in the sweet agony of coitus. Rest assured that any aspects of our sexual relationship regarding your preferences, your idiosyncrasies, your performance, are still protected by the inherent confidentiality of the bedroom.

Leonard: I call Frodo!
Sheldon, Raj, and Howard: Damn!

Leonard: We all have other costumes, we can change.
Raj: Or we could walk right behind each other all night. It'll look like one person going really fast.

Penny: She'll have sex with anyone as long as they keep buying her things.
Howard: Really?
Penny: Yeah!
Howard: Yay! If you'll excuse me, I have some bar mitzvah bonds to cash.

Penny: I finally convinced the restaurant to give me a bar-tending shift, so I need to practice mixing drinks.
Leonard: That's Great! The key to acquiring proficiency in any task is repetition.
Sheldon: With certain obvious exceptions. ... Suicide, for example.