Penny: Oh, please. When I first met you, you were incapable of touching another human being. Now you're holding hands, going on dates, you even made out with her on a train.
Sheldon: She told you?
Penny: Of course she told me. It's the most interesting thing that's ever happened to her in her entire life.

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?

Bernadette: I think what we're all trying to say is that you don't seem to be remembering how traumatic the experience was for you.
Raj: Like how women often forget the pain of childbirth.
Mike Rostenkowski: Like a woman. Great analogy.

Sheldon: I've changed. Like the frog who's put in a pot of water that's heated so gradually, he doesn't realize he's boiling to death.
Penny: Or you're the frog who's been kissed by the princess and turned into a prince.
Leonard: Or you're just a tall, annoying frog.

Amy: I'm not surprised you want to end the relationship. I'm a little surprised you didn't get AppleCare.