Penny: Sing Soft Kitty to me.
Sheldon: Soft Kitty is for when you’re sick. You're not sick.
Penny: Injured and drugged is a kind of sick.
Sheldon: [sings] Soft kitty, warm kitty, little ball of fur…
Penny: Wait, wait. Let's sing it as a round. I'll start. [sings] Soft kitty, warm kitty, little ball of fur… See that's where you come in. I'll start over. [sings] Soft kitty, warm kitty, little ball of fur… I've got all night, Sheldon. Soft kitty, warm kitty…
Both: [sing] ...little ball of fur, happy kitty, sleepy kitty, purr, purr, purr.

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

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?

Howard: I'm not signing a prenup.
Penny: All right, Howard Wolowitz, listen up! You sign anything she puts in front of you, because you are the luckiest man alive. If you let her go, there is no way you can find anyone else. Speaking on behalf of all women, it is not going to happen, we had a meeting.

Raj: If I could speak the language of rabbits, they would be amazed, and I would be their king.
Leonard: I hate my name. It has 'nerd' in it. 'Len. Nerd.'
Wolowitz: I lost my virginity to my cousin Jeanie.
Raj: I would be kind to my rabbit subjects. At first.

Wolowitz: You're such a douche
Raj: Who cares? You slept with your cousin!

Sheldon: Now remember, you were given powerful pain medication and a muscle relaxer, so don't operate heavy machinery, and try not to choke on your own drool. [goes to leave] Penny: Wait! You have to help me get into bed. [laughs] "Sheldon has to help me get into bed". Bet you thought I'd never say that!
Sheldon: Yes. Charmed. Your drug-addled candor knows no bounds. [helps Penny into bed]
Penny: You know people think you are this weird robot man who's so annoying all the time and you totally are. But then it's like that movie Wall-E at the end. You're so full of love and you can save a plant and get fat people out of their floaty chairs.
Sheldon: That's a fairly labored metaphor but I appreciate the sentiment behind it.