Sheldon: All right, are you familiar with the development that resulted from Honore Blanc's 1778 use of interchangeable parts? The assembly line, of course.
Penny: Okay, you know what, if I'm not allowed to be snide, you're not allowed to be condescending.
Sheldon: That wasn't a part of our original agreement, and I do not agree to it now.
Penny: All right, fine. How are we supposed to set up machines and conveyor belts in my apartment?
Sheldon: You're thinking of the moving assembly line, an understandable but not excusable mistake. No, the moving assembly line, that was introduced by Henry Ford in 1908. That innovation is what made possible our modern consumer culture by enabling a low-unit cost for manufactured goods. I guess that isn't one of the topics discussed on your Radiohead.

Sheldon: Of all the overrated physicists in all the labs in all the world, why does it have to be Leslie Winkle?

Leonard: I would appreciate it if you would, you know, make yourself scarce.
Sheldon: Leonard, I am a published theoretical physicist with two doctorates and an IQ which can't be accurately measured by normal tests, how much scarcer could I be?

Raj: Actually, in India, the names of constellations are different. Where you have the Big Dipper, we have the Big Curry Pot.
Summer Glau: You're making that up.
Raj: You got me. Now what are you going to do with me?

Penny: The theater is above a bowling alley, so it's a little noisy, but it might be the only chance I'll ever get to play Anne Frank. And the director is brilliant. He uses the bowling sounds as, like, Nazi artillery.

Sheldon: Here’s a fun question. Do you know what the most common street name is?
Penny: No.
Sheldon: The answer's tricky. It's Second Street. You see, you'd think it would be First Street, but in most towns, First Street eventually gets renamed to something else, you know, like Main Street, Broad Street, Michigan Avenue.

Sheldon: That is my spot. In an ever-changing world, it is a single point of consistency. If my life were expressed as a function on a four-dimensional Cartesian coordinate system, that spot at the moment I first sat on it would be zero-zero-zero-zero.

Mrs. Wolowitz: Okay then, you kids have fun. Use protection!

Leslie: Hey, are you enjoying that prototyper I got you?
Howard: Oh, it's great. Everybody in the Engineering Department is eating their hearts out.
Leslie: Isn't it nice when your good fortune makes others miserable?
Howard: You know, most people don't get that.

[Sheldon moves around the movie theater, sitting in various seats and emitting various noises]
Steph: What is he doing?
Leonard: He's finding the "acoustic sweet spot".
Steph: Does he always do this?
Leonard: Sometimes he brings a toy xylophone. I am really sorry about this.
Steph: No, it's fine. You know, he's sweet.
Sheldon: My apologies, you've been sitting in it all along. Leonard, you want to slide over one?
Leonard: No, just sit here.
[As the movie begins, Sheldon cranes his neck over to experience the sound in Leonard's seat]
Sheldon: Oh, yeah, this is it.

Leonard: Why don't you just tell her to leave you alone?
Sheldon: I did. I told her, I texted her, I sent out a very emphatic twitter. I even changed my Facebook status to Sheldon Cooper wishes Penny would leave him alone. I don't know what else to do.

Penny: Honey, you'll be fine as long as you don't do that bungee cord thing, okay?
Sheldon: Penny, didn't you recently state that you and I are friends?
Penny: Yes, Sheldon, we are friends.
Sheldon: Then I hereby invoke what I'm given to understand is an integral part of the implied covenant of friendship. The favor.
Penny: Oh, dear God.
Sheldon: I'm sorry. I didn't realize I was interrupting your morning prayers. When you're done, we'll go.

Raj: But if we were part of the team that confirmed string theory, we could drink for free in any bar in any college town with a university that has a strong science program.

Leonard: So, Mother, what's new?
Beverly Hofstadter: You'll have to be more specific.
Leonard: All right. Uh, what's new with you?
Beverly Hofstadter: Oh, well, I've been having some fascinating menopausal symptoms recently.
Leonard: Maybe something less personal.
Beverly Hofstadter: Oh. Your Uncle Floyd died.
Leonard: Oh, my God. What happened?
Beverly Hofstadter: His heart stopped beating. I have to urinate.

Leonard: I've dated plenty of women. There was Joyce Kim, Leslie Winkle.
Sheldon: Notify the editors of the Oxford English Dictionary. The word plenty has been redefined to mean two.