Penny: That was such a fun night.
Leonard: Probably 'cause you got to see your man up there rockin' the mic.
Penny: Yeah, yeah. I was a little surprised when you decided to beat-box.
Leonard: Oh, that was really an asthma attack. I just sold it.

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: 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.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

Penny: Oh, it's Leonard. He says Sheldon's drunk and they're gonna do karaoke if we want to join them.
Penny: That sounds fun.
Amy: Oh, no. Sheldon's drunk texting me.
Bernadette: What's it say?
Amy: "Would you like to sing karaoke with us."
Bernadette: How is that a drunk text?
Amy: He used a period instead of a question mark. He's so wasted.

Raj: Look at that. You've known you're gonna be a father for less than a day and you're already stepping up.
Leonard: I'm telling you, you got this.
Howard: Maybe you're right.
Sheldon: Of course he's right. You and I both know how hard it is growing up without a father. That's why I'm confident you're gonna be the best dad you can be.
Howard: Thank you, Sheldon.
Sheldon: You're welcome. And if he has twins, we can do all kinds of neat experiments on them.

Amy: Are you hungry? How about that sushi place you love?
Bernadette: Doctor said I can't have sushi.
Penny: Okay, look, we don't have to go anywhere. We can just, you know, stay here and hang out in the hot tub.
Bernadette: Doctor said I can't go in the hot tub.
Amy: Maybe you should get a new doctor. What, he said you can't laugh either?