Amy: I'm saying, in the spirit of science, what is that little skank's problem?

Sheldon: If you've got a problem basing a relationship on a contract, I'd like to tell you about thirteen plucky colonies that entered a relationship agreement called the U.S. constitution. And it may not be cool to say so, but I think that love affair's still pretty hot today.

Amy: It would make me so happy if you said things like that.
Sheldon: We got an 8.2. Trust me, you're happy.

Leonard: You didn't lose anyone when you met Amy.
Sheldon: The study refers to romantic partners. That's not the way I would categorize the two of us.

Raj: I have an idea.
Sheldon: I think I have the same one.
Howard: We've got to watch Back to the Future II.
Raj: I'll make the pop corn.

Raj: Where's Sheldon?
Penny: Date night.
Leonard: That can't be much fun for Amy. You know at work today he tried his first Redbull.
Bernadette: What happened?
Leonard: He chased a squirrel around the quad for a while. And then threw up in my car.

Bernadette: Shall we tell everyone not to come?
Howard: No, I wanna do this.
Bernadette: Okay. I'll keep it together if you can.
Raj: I'm not making any promises.

Sheldon: Leonard, I've been working on an opening joke for our lecture at Berkeley.
Leonard: Oh, I like to laugh. But say it anyway.

Sheldon: What do you say to a graduate of the U.C. Berkeley Physics Department? I'll have fries with that. Because his education hasn't prepared him for a career in the sciences.

Penny: You still worried some Berkeley girl's gonna steal him away?
Amy: Yes. Who do you think gave him the danger whistle?

Sheldon: Would you like to play a physics car game I invented called "I Can't Spy?" It's all the nail-biting tension of I Spy but the added fun of sub-atomic particles and waves outside the visible spectrum.
Leonard: If it's half as much fun as "1 x 10 to the 4th bottles of beer on the wall", I'm in.

Bernadette: Don't listen to him. All she's got is a serve. Now grab a fresh tampon and put her away.

Raj: What makes them think they're always in charge of everything?
Leonard: They're alpha males.
Raj: What does that make us?
Leonard: We could be betas. They're second in charge.
Raj: Okay, that sounds good.
Leonard: Or we could be omegas. They get pushed around by the alphas and the betas.
Raj: Okay, that sounds like us.

Penny: I like pharmaceutical sales. It's going great, but I have an audition for a movie, and if I get it, it could screw everything up.
Sheldon: Hmm. I know exactly what you should do. Unfortunately, I cannot tell you.

Sheldon: Perhaps you'd prefer this one. The itzy-bitzy spider is not an insect at all. Because it has eight legs and two body parts.