Leonard: This train thing worked out better than I thought. He's home studying the engineer's manual.
Howard: It's so peaceful without him here. Can I ask you how much that cost?
Leonard: $4,000. Worth every penny.

Raj: Okay, you ladies have fun tonight.
Stuart: Don't worry about Halley. Uncle Stuart's on the job.
Raj: Under the careful supervision of her godfather.
Stuart: My apologies. I didn't mean to offend you, Don Corleone.

Stuart: Okay, instead of arguing all night, let's just split up the baby chores.
Raj: Yeah, great. Um, I'll put food in her top half, you deal with whatever comes out the bottom.

Leonard: (electrical crackling) What is that?
Howard: I don't know, but if he yells, "It's alive," we run.

Leonard: Okay, look, Sheldon, the Colonel wants us to make the guidance system smaller, and we can't do it without you.
Sheldon: Interesting. So I was right.
Howard: Open a window. It's about to get smug in here.

Amy: Did you hear anything back from the Caltech preschool?
Bernadette: Not yet, but we're gonna apply to a bunch of others just to keep our options open.
Penny: Okay, stop that! No more preschool talk. Tonight is about having fun.
Amy: Nothing says fun like being scolded.

Stuart: So we just throw this away?
Raj: What else are you gonna do with it? Put it in your coffee?
Stuart: Well, I don't take it black.

Penny: Sorry, guys. This club was so great. How could they turn it into a bookstore? I thought we got rid of all those.

Raj: Little parenting tip: sleeping babies hate flash photography.

Penny: Is everything okay?
Bernadette: Yeah. I may have just left my infant daughter with Patrick and SpongeBob.

Bernadette: You're upset I had a baby?
Penny: No, of course not. I just I didn't think it would make me have all these feelings.
Amy: What feelings?
Penny: Pressure! I mean, she's looking at preschools, she has a minivan, she has a 401(k). Before she talked about it, I just thought that was a race.

Leonard: Aren't you gonna look at the board to see how right we are?
Sheldon: No, thanks. I'm busy trying to fix this fuel pump.
Howard: It's a manifold.
Sheldon: Oh. Well, I guess it's fixed.

Leonard: Just look at the board.
Sheldon: That's wrong.
Leonard: Oh, no! What should we have done differently?
Sheldon: Well, first of all, you can't use relativistic and non-relativistic vectors in the same equation.
Howard: Told ya. (scoffs) Can you fix it for us?
Sheldon: (sighs) Okay, but this is the last time. (Draws Charlie Brown's face on the squiggle Leonard drew on the board) Nice try, blockheads.

Leonard: So, what do you say?
Sheldon: Oh, what choice do I have? You need me. (pointing to the engine) I'm like the crankshaft of this team.
Howard: That's a turbo.
Sheldon: Well, whatever it is, it looks heavy. I'm gonna need you two to get it downstairs before Amy comes home.

Amy: Hey, there's another dance club nearby. I mean, I don't know how you feel about Latin music, but according to their "horas of operacion", they're open.
Penny: Maybe we should just call it a night.
Amy: You sure? They're open till dos.