Leonard: You can't think this is the right time to "validate his behavior."
Penny: Okay, what about "presenting a united front"?
Leonard: What about you coddling him and he's never gonna learn?
Penny: Look, you sound frustrated, and I'm really proud of the way you're able to state your opinion.
Leonard: Thank you. Wait, no, no. Don't use that book on me!

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.

Penny: No, I've been reading Bernadette's parenting book. It's like the answer key to the Sheldon test.

Leonard: It's fine, I've been driving him for years. What's one more day?
Sheldon: Oh, and I've got a new car game we can play. It's called "What siren am I?"

Sheldon: All right, you ready for your next one? Just a warning, this one's a little annoying. (imitates a high-pitched siren)
Leonard: Let's take a little little break, I'm getting a headache.
Sheldon: Aw, right in the middle of our fun game.
Leonard: Yeah, weird.