Penny: Is it possible that the sleep-talking is a part of your brain that's telling you everything's gonna be okay and you just need to relax a little?
Sheldon: So you're proposing that the self is an illusion, and that we actually have multiple centers of consciousness that are communicating with one another?
Penny: In laymen's terms, yeah.
Sheldon: Huh. Interesting. So you don't believe there's a Cartesian self that underlies the flux of experience?
Penny: Maybe in my twenties, not anymore.

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: One of the great things about being pregnant is drinking cranberry juice out of a wineglass and watching people freak out.

Penny: Is it possible that you're stressed because you're scared about getting married? I mean, it is a big change, and you're not good with little changes.
Sheldon: Well, that's nonsense. You name one little change I was upset with.
Penny: Uh, when they changed the green Skittle from lime to apple.
Sheldon: That is not the rainbow I grew up tasting.

Howard: It's a date. Just pick one.
Sheldon: It's not just a date, it's a textbook optimization problem. There is a perfect date. Just like there's a perfect room temperature and a perfect dessert.
Penny: Mm. There's no perfect dessert.
Sheldon: Yellow cake in the shape of a dinosaur with chocolate frosting, a scoop of vanilla ice cream on the side, not touching. You'll see. You'll have it at our wedding.
Amy: You wanna bet?