Raj: Well, so you're on his side?
Penny: I'm just saying, that's what friends do. You know, they bust on each other. It doesn't mean anything.
Leonard: Well, I'm not surprised you think so.
Penny: Why is that?
Leonard: Well, you can be kind of mean to me.
Penny: Well, that's because you're- Wow. I don't know how to finish that sentence, either.

Sheldon: Woman, you are playing with forces beyond your ken.
Penny: Yeah, well your Ken can kiss my Barbie.

Raj: [to Amy] If you were having Sheldon's baby, would you really want him in the room?
Penny: Yeah, if he's in the room when they're making the baby, I'll give you $10.

Penny: I mean, who even reads Scientific American?
Leonard: It's kind of a big deal.
Penny: If it's such a big deal, how come the biggest celebrity they could get for the cover is a molecule?

Sheldon: I mean, it's not that I think we're living in sin, but I do like the idea that our next act of intimacy will be a legal requirement.

Amy: Maybe we should just get married at City Hall and forget about everything else.
Sheldon: City Hall, hmm. I do like metal detectors and the sound of permits being denied.

Sheldon: Neither of them will be the actual cake. I'm just using it as a bargaining chip to get Amy to agree to the whole wedding party getting rings and us getting one ring to rule them all.
Howard: I forget, which mental hospital are you guys registered at?