Penny: I like hanging out with you guys, but I'm not gonna apologize for something I didn't do.
Leonard: Well, actually, technically, you did do it.
Penny: That's strike one, Leonard.

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

Leonard: What am I supposed to do?
Penny: Err, keep your mouth off other women.

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

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

Wolowitz: If it's "creepy" to use the Internet, military satellites, and robot aircraft to find a house full of gorgeous young models so I can drop in on them unexpected, then fine, I'm "creepy".

Penny: Here you go, [to Leonard] quesadilla, [to Howard] salad, [to Raj] here's your pizza. And thanks to Sheldon's heated discussion with my manager, one barbecue bacon cheeseburger, barbecue sauce, bacon, and cheese on the side.
Sheldon: Thank you!
Penny: Go ahead. Eat it. I dare you!