Sheldon: The Hindu Code of Manu is very clear in these matters. If a woman's father is not around, the duty of controlling her base desires falls to the closest male member of her family. In this case, Raj. The code also states that if she disobeys, she will be reborn in the womb of a jackal and tormented by diseases. If true, that seems like an awfully large gamble given that the prize is Leonard.

Sheldon: Ladies and Gentlemen, honored daughters. While Mr. Kim by virtue of his youth and naivete has fallen prey to the inexplicable need for human contact, let me assure you that my research will go on uninterrupted, and that social relationships will continue to baffle and repulse me. Thank you.

Penny: Look, just forget I told you about me not graduating from community college, okay?
Sheldon: Forget? You want me to forget? This mind does not forget. I haven't forgotten a thing since the day my mother stopped breast-feeding me. It was a drizzly Tuesday.

Sheldon: Until you either do not go or go to Wil Wheaton's party you are simultaneously my friend and not my friend. I'm characterizing this phenomenon as Schrodinger's Friendship.

Sheldon: If you're interested I can send you a link to a YouTube video that would show you how to perform your own rectal exam. Helpful hint: trim your nails first.

Sheldon: I can't believe he fired me.
Leonard: Well, you did call him a "glorified high school science teacher whose last successful experiment was lighting his own farts."
Sheldon: In my defense, I prefaced that with, "with all due respect."

Sheldon: Hawaii is a former leper colony on top of an active Volcano where the disappointing ending to Lost was filmed. Mahalo for nothing, Hawaii.

Sheldon: Is your womb available for rental?

Leonard: You cannot blow up my head with your brain.
Sheldon: Then I'll settle for an aneurysm.

Leonard: It's going to be difficult to find something you are both equally good at.
Raj: Is there anything you are both equally bad at?
Sheldon and Kripke: Sports.

Sheldon: Everyone knows that I'm our group's resident cut-up.

Sheldon: That's my parking spot.
Raj: Why do you have a parking spot? You don't have a car. You don't even drive.
Leonard: Maybe they reassigned it because you never use it.
Sheldon: Well, I'm not using my nipples either. Maybe they should reassign those.

Stuart: Here, Sheldon, I pulled the new Hellboy for you. It's mind-blowing.
Sheldon: Excuse me. Spoiler alert.
Stuart: I didn't spoil anything.
Sheldon: You told me it's mind-blowing.So, my mind is going into it pre-blown. And once a mind is pre-blown, it cannot be re-blown.
Stuart: I'm sorry.
Sheldon: Said the Grinch to Christmas.

Sheldon: Yeah, I'm definitely going with colonoscopy.
Leonard: Okay, bye. (Off the phone) My mother's coming for a visit.
Howard: How about that, you were right.

Sheldon: Like the subordinate male protagonist in countless action movies who disappears halfway through the second reel, I have returned to save the day. [pause]. Odd, he's usually met by cheers.