Penny: What am I supposed to say?
Leonard: Say "Can't talk right now, hanging with my boyfriend. England sucks. You suck. USA number one."

Leonard: Set your phasers to stun. If we vaporize Penny, I'll never get a girlfriend that pretty again.

Amy: Well, at least when we do make love, Sheldon won't be thinking about his mother. And yes, that is a cleverly veiled reference to Howard's lifelong obsession to crawl back into her spacious womb.

Bernadette: Hey, Howie, how you feeling?
Wolowitz: Better. Much better. The other astronauts held me down, gave me a shot. Oooh. Attention, people of Earth. Tonight, there will be two moons in the sky.
Bernadette: Howie, stop that. NASA's watching this! Put your pants back on!

Wolowitz: If I die, promise me you'll never have sex with another man.

Leonard: Penny started taking a class. She wrote a paper, she didn't want me to read it, I went behind her back and I read it anyway.
Sheldon: Stephen Hawking hates me.
Leonard: I don't know what to do. I mean, the paper's terrible. But if I tell her, she'll know that I read it and she'll get really mad.
Sheldon: I was beating him so bad, he doesn't want to be friends anymore. Why does everyone love me except Stephen Hawking?
Leonard: Is it possible we're having two different conversations?
Sheldon: How would I know? I'm not listening to you.

Leonard: Oh, you do what you want. But I don't want to lose my friends over tenure. Friends are forever.
Howard: *Coughing* So is tenure.

Raj: I did the research. Tony the Tiger, Dig'em the Frog, Cap'n Crunch, Toucan Sam, Count Chocula, Trix the Rabbit, Snap, Crackle and Pop. Not one cereal mascot is a girl. It's a total breakfast sausage fest.
Leonard: Are we done with this?
Raj: Almost. Franken Berry, Boo Berry, Sugar Bear and the Honey Nut Cheerio bee, I believe his name is Buzz.

Sheldon: Svaty Vaclav is better known as Good King Wenceslas from the beloved Victorian Christmas carol.
Howard: Never heard of it. Must be the one Christmas song not written by a Jewish guy.

Amy: Excuse me, but I'm a neurobiologist. I think I'm a little more qualified to understand what's not working in your girlfriend's brain.

Bernadette: You can't just throw everything in the closet.
Howard: Hey, you can tell me what to do and how to do it, but not both at the same time. This isn't sex.

Leonard: I know what the anthropic principle is.
Sheldon: Of course. I just explained it to you. Now, where do you stand on it?
Leonard: Where do you stand on it?
Sheldon: Strongly pro.
Leonard: Then I believe that God created the world in six days and on the seventh he made you to annoy me.

Stuart: My carpal tunnel is acting up.
Sheldon: Play through the pain.

Amy: And action.
Wil Wheaton: And cut! You realize I'm doing this for free, right?
Amy: Yes, and so far we're still not getting our money's worth.

Penny: Once again, unbelievable.
Sheldon: Yeah, once again, I know.