Penny: Wait, what is going on?
Sheldon: In case you have forgotten, Schrodinger's cat is a thought experiment.
Penny: No, no, no, no, I didn't forget. Um, there's this cat in a box and until you open it, it's either dead or alive or both. Although, back in Nebraska, our cat got stuck in my brother's camp trunk, and we did not need to open it to know there was all kinds of dead cat in there.
Amy: Homespun stories, knowledge of physics and a bosom that defies it. You're the whole package, aren't you?

Sheldon: This will just take a moment, it's on a five and a quarter inch floppy.
Amy: A floppy disk?
Sheldon: Well, I started the list when I was nine.

Sheldon: [to Brent Spiner] You are now my mortal enemy.
Wil Wheaton: Don't worry it doesn't take up too much of your time.

Amy: Now Sheldon, I know you're a left handed monkey wrench but you seriously have a mortal enemy
Sheldon: Yes, in fact I have 61. Would you like to see the list?

Amy: It's not for us to judge. We're just here to provide comfort and support while you come to grips with what a despicable thing you've done.

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.

Leonard: Going to Wheaton's party is not betraying you.
Sheldon: Oh, of course you would have to believe that. Evil always thinks it's doing right. Excuse me, Stormtrooper. These are the droids you're looking for.
Leonard: I'm going to a party. I'm not turning R2-D2 and C-3PO over to the empire!
Sheldon: Not yet.

Bernadette: Oh, boo-hoo, you're not going to space!

Sheldon: You just got off the list, would you like back on it?

Mrs. Wolowitz: Over my dead body my son goes into outer space.

Wil: Hey, I'm having a party at my house on Friday, and I was hoping you would stop by.
Stuart: Will there be girls there?
Wil: Yeah, of course.
Stuart: 'cause there wasn't last time.
Wil: There will be girls.

Amy: How did Wil Wheaton get on the list?
Everybody: Oh!
Sheldon: As a child, I loved Wesley Crusher, Wil Wheaton's character on Star Trek. So, I drove for hours by bus to a Star Trek convention at which Wil Wheaton was scheduled to appear, so that I could get my Wesley Crusher action figure signed. But he never showed, because apparently, it was cooler for him to be the lower-left corner on Hollywood Squares.
Oh, damn! The floppy failed. Well, whoever was in charge of quality control at the Verbatim Corporation in 1989, congratulations, you just made the list.

Leonard: All right, Sheldon, we're going to Wil's. This is your last chance.
Sheldon: No, Leonard, this is your last chance. One day, a historian is going to come to you and say, is it true you were friends with Dr. Sheldon Cooper? And you're going to have to choke back a hot sob of regret and humiliation as you mumble, I was, but I chose to go to a party thrown by the one kid from Stand By Me that no one remembers.

Leonard: Two ten and you throw in the Iron Man helmet.
Stuart: Are you crazy? That helmet's signed by Robert Downey Jr.
Leonard: So?
Stuart: Okay, if you're going to question the importance of an actor's signature on a plastic helmet from a movie based on a comic book, then all of our lives have no meaning!

Mrs. Wolowitz: Make up all you want. Your tuchus is not leaving this planet.