Penny: So, what ya doing? Better not be building a robot girlfriend.
Leonard: No. Although Howard was making some real strides in that area until he met Bernadette.
Penny: You're kidding.
Leonard: Nope. Now the Lisatronic 3000 just sits in a box waiting for the phone to ring.

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Leonard: My point is, while you're spending all this time on your own, building computers or practicing your cello, what you're really doing is becoming interesting. When people finally do notice you, they're gonna find someone a lot cooler than they thought. And for those of you that were popular in high school, it's over, sorry. Thank you. Congratulations.

Stuart: Hey. Hey, look at you guys!
Amy: I'm Raggedy Ann, and he's Raggedy C-3PO.
Sheldon: It was a compromise. I lost.

Howard: A week ago, I was an astronaut.
Bernadette: Yeah, well, today you're a Smurf! Keep moving!

Howard: Okay, here it is. Bernadette said you guys are all sick of me talking about my trip to space. Is that true?
Sheldon: Yes.
Raj: No.
Sheldon: We seem to have different approaches here. I was going for helpful honesty. I have no idea what you're doing.
Raj: It's called being nice.
Sheldon: Okay. If you think being nice will get him to shut up, I'll try it.