Sheldon: Amy Farrah Fowler has asked me to meet her mother.
Leonard: Yeah, so?
Sheldon: What does that mean?
Leonard: Well, you know how you're always saying Amy is a girl who is your friend but not your girlfriend?
Sheldon: Uh huh.
Leonard: Well, you can't say that any more.

Raj: Hands off my sister.
Sheldon: Why would I touch your sister? She's all covered in airplane germs.

Sheldon: Einstein defined insanity as doing the same thing over and over again and expecting different results. By that definition, Penny is cuckoo for Cocoa Puffs.

Amy Farrah Fowler: Did you know the iconic heart shape isn't based on an actual human heart, its based on what a woman's rear end looks like bending over
Penny: So in 8th grade, I was dotting my i's with little asses? That's cool.

Howard: You gotta like this: the girlfriend, the ex-girlfriend, bonding over your rooty-tooty stinky booty? (All but Leonard laugh)
Leonard: Kill me.
Sheldon: It wouldn't help. The human body is capable of being flatulent for hours after death.

Sheldon: There's no need to interact with me. I'm just here to observe.

Raj: Oh, you're so arrogant. If you were a super hero your name would be Captain Arrogant. And do you know what your super power would be? Arrogance.

Penny: Hey. Nice knees.
Sheldon: Thank you! They're my mother's.

Todd Zarnecki: Who is it?
Sheldon: Your doom.

Sheldon: What are you doing here?
Howard: I've been up all night. I had a fight with Bernadette.
Sheldon: Why?
Howard: She bought me a nice watch.
Sheldon: Leonard, do you understand any of this?
Leonard: Yes.
Sheldon: Talk to him.

Sheldon: Well that's no threat, my mother's always wanted a grandchild.
Penny: Really? Your deeply religious born-again Christian mother wants a test-tube grandbaby born out of wedlock?
Sheldon: Curses.

Sheldon: That's going to make me a chick magnet and I'm so busy as it is.

Sheldon: I believe I may have cholera.
Leonard: There's no cholera in Pasadena. Just like last summer when there was no malaria in Pasadena.

Sheldon: Oh! There isn't enough chamomile tea in the world to quell the rage in my heart.

Sheldon:Excuse me, Penny, but "Doodle Jump" is a game. "Angry Birds" is a game. "World of Warcraft" is a massively multiplaying online role-playing... All right, technically it's a game.