Penny: So that means, you're a doctor, you're a doctor, you're a doctor, you're a doctor and, Howard, you know a lot of doctors.

Sheldon: Here's an interesting fact about alcohol: Man is not the only species that ferments fruit in order to become intoxicated. Can you guess what the other is? Hint: sometimes they pack the alcohol in their trunks.
Penny: Monkeys.
Sheldon: When does a monkey have a trunk?
Penny: When a suitcase just won't do.

Raj: Can I bring girls here?
Leonard: You? Sure. Bring as many as you want.
Raj: Okay, deal.
Leonard: Just not against their will.

Penny: What do you mean new roommate? What happened to Leonard?
Sheldon: The same thing that happened to Homo Erectus. He was replaced by a superior species.
Raj: I'm the new homo in town.

Leonard: What's going on?
Penny: Oh, hey, it's not what it looks like. *Leaving*
Sheldon: What does it look like?

Leonard: What are you doing here?
Raj: I was sleeping.
Leonard: In my bed?
Raj: Well, I would have slept in my own bed, but it was being used to bring shame to my family and the memory of Gene Roddenberry.

Sheldon: What are you doing here?
Howard: I've been up all night. I had a fight with Bernadette.
Sheldon: Why?
Howard: She bought me a nice watch.
Sheldon: Leonard, do you understand any of this?
Leonard: Yes.
Sheldon: Talk to him.

Mrs. Koothrappali: I'll sleep so much better when you move back here next month.
Leonard: You're moving back to India?
Dr. Koothrappali: Who's that?
Mrs. Koothrappali: Oh my God! There's someone in your apartment. Call the police in America!

Raj: Well, uh, to paraphrase Shakespeare, "It's better to have loved and lost than to stay home every night and download increasingly shameful pornography."

Sheldon: What are you doing here?
Leonard: I live here.
Sheldon: I have paperwork that says differently.

Amy: I study the brain, the organ reponsible for Beethoven's 5th Symphony. Bernadette studies yeast, the organism responsible for Michelob Light.

Leonard: If I roll down the windows, everything is peachy. If you roll down the windows, you're still not a doctor.

Raj: Rotting Zombie. Sheldon's new Facebook picture.

Raj: Sheldon, that's my water.
Sheldon: Oh, dear Lord!
Leonard: That's not your water.
Raj: I know.

Bernadette: All right. Here you go. Two lemonades, one iced tea and a root beer for Priya.
Priya: Is it diet?
Bernadette: That's what you ordered.