Sheldon: No, I know, but plenty of things are addictive after a single exposure. I mean, crack cocaine, nicotine, Pringles. You know, once one pops one just can't stop.

Howard: It's pretty late. You think I've got time to run some more simulations on the cooling system?
Leonard: Sure, I'm still figuring out the thermo-acoustic expander.
Sheldon: Oh, while you do that I am going to pump cerebral spinal fluid through my brain cells to remove the metabolic by-products of the day's thoughts.
Howard: What?
Sheldon: It's called sleep and it's my bedtime. Nighty-night, y'all.

Penny: Now Sheldon's popular? What is happening?!

Bernadette: Sorry I flipped out on you. I think it's just hormones.
Raj: I think you were mean before you were pregnant, but it's fine.

Howard: Sir, we've hit a bit of a snag. We're already behind schedule.
Sheldon: The computations required to overcome the deployability issues are more significant than we thought.
Leonard: I understand that we're under contract, and I don't know what the consequences of violating that are, but, uh we're not gonna be able to deliver in the time we promised.
Colonel Williams: (gets up and sighs) How long do you need?
Howard: We're thinking two years.
Colonel Williams: All right.
Howard: (chuckles) That's it? You're okay with that?
Colonel Williams: (scoffs) You think you're the first government contractor who isn't gonna deliver on time? We're still waiting for a big space laser Reagan ordered to beat the commies.

Bernadette: Not every girl dreams about being a mom. Sometimes you think you're never gonna have kids and one day you wake up and you're pregnant. And it doesn't matter that your career's going great right now and that you and your husband never even got to go anywhere taped to a dog!

Bert: It makes sense you two are friends. I mean, hot girls always stick together.
Amy: And you thought this wasn't gonna be a great party.
Penny: You know, I had no idea Caltech is exactly like my high school.
Amy: Well, it's not exactly like it. We're all extremely smart.
Penny: Wow. You popular girls are mean.

Bert: Okay, well, thanks for coming by. You're nice people.
Penny: Well, so are you. In fact, you know what? We will never take you for granite. Did you get that? Granite? A little geology joke.

Bernadette: But I thought I'd be more excited.
Dr. Koothrappali: Oh, being excited isn't a guarantee of anything. Rajesh's mother was thrilled when she was pregnant with him. After he was born, she doted on his every move. And you know what happened? He broke her heart, moved halfway around the world, and dates only poor white women. So you never know.

Penny: It's okay, I'll still go.
Leonard: You don't think you'll be bored?
Penny: Oh, I'll have some wine and listen to people go on about crap I don't understand. I mean, how is it any different than every single day of my life?
Sheldon: I won't be there.
Leonard: Look at that, it is a party!

Bernadette: I don't even know where to begin.
Raj: Well, in The Sound of Music, Julie Andrews says, "Let's start at the very beginning. A very good place to start."
Bernadette: Oh, I was gonna start at the end. Thank God you're here.

Raj: But anyway why don't we just take a step back and start with a color? Right? There are so many amazing ones. Red, blue, green, purple-
Bernadette: Are you just gonna name all the colors?
Raj: Well, not now.

Howard: Hey, hey, hey, you're not going anywhere.
Leonard: We only have two months to deliver this to the Air Force because of you.
Sheldon: (yawning) I know, I was there.
Howard: Well, wake up! We're gonna put in a lot of late nights.
Sheldon: How late?
Howard: Well, I don't know, midnight, one.
Sheldon: One o'clock? I'm not a raccoon.

Sheldon: I had a bad dream that my best friend became a tyrant and forced me to stay up all night to work.
Leonard: I had a good dream that when I carried you to bed, I let your head hit the wall and I laughed.

Penny: Oh, I'll go. I like a party.
Amy: Well, to be honest, it's not like a "party" party. It's more like a gathering where scientists of different disciplines get together to share their work and keep current on what's going on in other fields. I don't know why I called it a party, sorry.