The Big Bang Theory Season 5 Episode 10

Wolowitz: It's amazing people keep coming to comic book stores instead of just downloading comics digitally.
Leonard: It's probably for the best. For a lot of these guys the weekly trip here is the only chance their mom has to go down to the basement and change their sheets.
Wolowitz: Oh, that reminds me, I get fresh sheets tonight. Yay!

Wolowitz: You interested in Amy?
Stuart: She didn't look through me with soul-sucking, ball-shrivelling hatred and contempt. I like that in a woman.

Leonard: You friended Stuart on Facebook?
Wolowitz: I thought you didn't like Facebook anymore.
Sheldon: Don't be silly, I'm a fan of anything that tries to replace actual human contact.
Raj: Please, you're looking at Facebook to find out how their date went.
Sheldon: Really? You think I care if a man, "shared a pumpkin latte with a dynamite lady"?

Sheldon: (to Amy) With the understanding that nothing changes whatsoever—physical or otherwise—I would not object to us no longer characterizing you as not my girlfriend.

Sheldon: (knocks three times)
Penny: Who do we love?
Sheldon: Penny. (knocks three times)
Penny: Who do we love?
Sheldon: Penny. (knocks three times)
Penny: Who do we love?
Sheldon: Penny.