Penny: God, can we please just say no longer seeing each other?
Sheldon: Well, we could if it were true. But as you live in the same building, you see each other all the time. The variable which has changed is the coitus.
Penny: Okay, here’s the protocol, you and I are still friends, and you stop saying coitus.

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.

Leonard: If I take it off, Sheldon wins.
Penny: Sweetie, every night you don't kill him in his sleep, he wins.

Raj: Hey, Leonard?
Leonard: Yeah?
Raj: I haven't had sex in a year.
Leonard: Where are you going with this, Raj?
Raj: Don't flatter yourself, dude.

Leonard: Hey, where've you been?
Sheldon: I was talking with Penny.
Howard: What's wrong with you? You can't hang out with your roommate's ex. That's totally uncool.
Leonard: No, it's fine. I don't care. I'm over it.
Raj: Yeah, he's over it; that's why he's been whining all day about trying to invent that memory-wiper gizmo from Men in Black.
Sheldon: Is he making any progress? Because I'd like to erase Ben Affleck as Daredevil.
Howard: So would Ben Affleck.

Penny: So, how've you been?
Sheldon: Well, my existence is a continuum, so I've been what I am at each point in the implied time period.