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

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: Don't worry about the moon. We, we set our laser to stun.
Zack: Smart.
Leonard: Now, we'll be able to see the beam when it leaves, but it won't be strong enough when it comes back to be seen by the naked eye.
Zack: (chuckling) Naked.

Zack: Is that the laser? It's bitchin'.
Sheldon: Yes. In 1917, when Albert Einstein established the theoretic foundation for the laser in his paper "Zur Quantentheorie der Strahlung", his fondest hope was that the resultant device be bitchin'.
Zack: Well, mission accomplished!

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

Raj: I'm telling you, dude. The only way to feel better about Penny going out with other guys is for you to get back on the whores.

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?

Amy: I don't object to the concept of a deity, but I'm baffled by the notion of one that takes attendance.

Penny: So Sheldon's last roommate tried to warn you off?
Leonard: For all I knew, he was the crazy one. He had this really deranged look.
Penny: Well, yeah. He'd been living with Sheldon.

Sheldon: When do you evacuate your bowels?
Leonard: When I have to.
Sheldon: When you have to? I'm sorry I don't rent to hippies.

Leonard: Not only did Sheldon save my life, he didn't rat me out to the landlord. Or the police. Or Homeland Security.
Penny: Okay, so, basically, you're the reason I have to walk up and down three flights of stairs every day?

Sheldon: That's where I sit.
Leonard: What's the difference?
Sheldon: This seat is ideally located both in relation to the heat source in the winter and a cross breeze in the summer. It also faces the television at a direct angle allowing me to immerse myself in entertainment or game play without being subjected to conversation. As a result, I've placed it in a state of eternal dibs.

Sheldon: That's correct. FYI, I would have accepted any answer other than procreating. Come, I'll show you the rest of the apartment.
Leonard: Oh, good. I passed the barriers.
Sheldon: The second barrier. Don't get cocky.

Leonard: There you go, three against one.
Sheldon: They don't get a vote. It's one against one. And according to the roommate agreement, all ties will be settled by me.
Leonard: But I said no to that.
Sheldon: And I said yes. And I settle all ties.

Sheldon: Third barrier passed. You have won the right to see your room. Huzzah!
Leonard: Is this it?
Sheldon: No, this is my room. People don't go in my room.
Leonard: So where do you sleep?
Sheldon: I don't understand.
Leonard: If people don't go in there, and you're people, and… You are people, aren't you? Making a joke.
Sheldon: Do you do this often?
Leonard: On occasion.