Leonard: Hey. I thought about what I want to do tonight, and I didn't take your feelings into consideration at all.
Penny: Great.
Leonard: I want to have sex.
Penny: Wow, sex with your wife. You're really swinging for the fences there, Hofstadter.

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?

Amy: Wow. Déjà vu.
Sheldon: Amy, you're a neuroscientist. you know the latest research into déjà vu suggests it's nothing but the frontal regions of the brain attempting to correct an inaccurate memory.
Amy: You telling me stuff I already know is definitely déjà vu.

Sheldon: How can I tell if I'm doing something for a noble reason or a selfish reason?
Amy: Try saying the thing in your head and see if you can add the words, "That'll show 'em."

Sheldon: Leonard's about to demand a job that I don't think the university will give him. I'm worried he's making a giant mistake. But maybe I only think that because deep down I don't want him to succeed.
Amy: The fact that you're worried about your motivation supports the idea that you genuinely care for your friend.
Sheldon: I do. Thank you, Amy. You know what? After I've talked to Leonard, you've earned yourself a bonus lecture on Sponge Hulk.
Amy: That'll show me.