Sheldon: I've been dreaming about going to the Large Hadron Collider since I was nine years old.
Leonard: Yeah, well, I've been dreaming about spending Valentine's Day with a girl since I was six.
Sheldon: Shame on you! That's no dream for a scientist.

Leonard: This tray contains clues as to what you and I are going to be doing on Valentine's Day.
Penny: Oh, wow. Okay. Let's see. We've got milk chocolate, Swiss cheese, fondue.
My lactose-intolerant boyfriend is going to eat all this, then I'm going to climb on his back and rocket to the moon?

Leonard: Who's miserable and alone?
Raj: Me.
Leonard: Oh, I used to be like that. Then I got a girlfriend.
Sheldon: In pre-1976 terms, neener-neener.

Leonard: Okay, I know what'll cheer you up, let's play one of your driving games.
Sheldon: All right. This game is called Traitors. I will name three historical figures, you put them in order of the heinousness of their betrayal. Benedict Arnold, Judas, Dr. Leonard Hofstadter.
Leonard: You really think I belong with Benedict Arnold and Judas?
Sheldon: You're right. Judas had the decency to hang himself after what he did.

Howard: Ow. Damn, paper cut. Nothing worse than a paper cut.
Raj: Well, obviously you don't remember your circumcision.

Howard: Sheldon, why do you have all these unopened paychecks in your desk?
Sheldon: Because most of the things I'm planning to buy haven't been invented yet.
Howard: But there must be thousands of dollars here. Why don't you put it in the bank?
Sheldon: I don't trust banks. I believe that when the robots rise up, ATMs will lead the charge.

Sheldon: Ill tell you where I've been. You boys may have had gelato with Stan Lee and gotten autographed comics, but I saw the inside of his house and got an autographed application for a restraining order.
Howard: Sweet.
Sheldon: Plus, I get to hang out with him again at the hearing. This is going to look great hanging next to my restraining order from Leonard Nimoy.

Sheldon: And next, if either of us ever invents time travel, we agree our first stop will be this meeting today in precisely five seconds.
Leonard: Okay. [They look around, nothing happens]
Sheldon: Well that's disappointing.

Raj: Go away. She wants New Delhi, not Kosher deli.

*Raj sneezes*
Sheldon: Hold.
Raj: What?
Sheldon: Explain your sneeze.
Raj: I'm sorry?
Sheldon: Do you have allergies?
Raj: No.
Sheldon: Is there too much pepper on your salad?
Raj: I don't put pepper on salads.
Sheldon: I've heard enough. Sit over there.

Sheldon: Vocal test. Morning vocal test. Second vocal test. Second morning vocal test.

Penny: You may be right about me and Leonard.
Sheldon: Of course I'm right What are the odds I'd be wrong twice in one week?
Penny: No, I mean, we can always go back to being friends.
Sheldon: I just said that. This conversation has started to circle. Meeting adjourned.

Leonard: You know what, go to Hell and set their thermostat.
Sheldon: I don't have to go to Hell. At 73 degrees, I'm already there.

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.

Crawley: Ha-ha. Don't knock, just walk in. Why be polite to the world's leading expert on the dung beetle?