Bernadette: How come the three of you never got an apartment together?
Leonard: We talked about it, but Howard was in a pretty serious relationship with his mom.
Howard: I lived with her to save money.
Raj: You didn't have to buy groceries because you were breast feeding.

I hope it's just a sprain. I cannot walk into that ER with another video game injury.

Leonard: I can't believe they kicked you out.
Raj: I can't believe they're still married.

Your element does not exist!

Sheldon: Well, I'm not just some trained monkey dancing for coins.
Leonard: Of course not. People love trained monkeys.

Penny: We had one of those silly fake weddings.
Leonard: Penny ... you know those are real, right?
Penny: No, they're not.
Leonard: Yeah, they are.
Penny: No, they're not.
Leonard: Yeah, they are.
Sheldon: He's right.
Amy: They're real.
Penny: But, it didn't seem real.

Leonard: It'd actually be nice to not hear Sheldon complain about my cooking all day.
Sheldon: Yo ... uh, excuse me, but every year you prepare a terrible meal and every year I criticize it. Do our traditions mean nothing to you?

Leonard: How about that? Sheldon's being reasonable.
Penny: Yeah, it's freaking me out. I'm gonna go.

Leonard: I'm gonna show you what's in the box, but just ... promise not to flip out.
Sheldon: Why would I flip out? Is it a spider? It's a spider.
Penny: No, if it was a spider, Lenny would've flipped out.

Dr. Jeffries: You ... you know you're describing a dog.
Leonard: He did bite me once.

Dr. Jeffries: W-why do you put up with Sheldon?
Leonard: Because we're friends.
Dr. Jeffries: Why?
Leonard: Wow. You ask really hard questions.

Leonard: Buddy, I don't think you can. I mean, once it's out there, it's out there. This thing is like the science equivalent of a sex tape.
Sheldon: You know, frankly, I'd prefer a sex tape.
Leonard: You don't know what a sex tape is, do you?
Sheldon: No.

TBBT Quotes

A neutron walks into a bar and asks, "How much for a drink?" The bartender says, "For you? No charge."

Sheldon

Penny: Hey, Sheldon, did you change your Wi-Fi password again?
Sheldon: Yes, it's "Penny, get your own Wi-Fi." No spaces.