Sheldon: I've invented a science joke. Would you like to hear it?
Amy: Sure.
Sheldon: How many Edisons does it take to screw in a lightbulb?
Amy: How many?
Sheldon: Who cares? He stole the idea and doesn't deserve his own joke.

Sheldon: But that doesn't mean that you should be standing on street corners, handing out your math to whatever guy comes along.

Penny: Besides, aren't you the one who says there's nothing more important than the advancement of science?
Sheldon: No, I said there's nothing more important than me advancing science.

Leonard: So you guys were testing us both? What is the matter with you?
Penny: What's the matter with them is they both think they're so smart, they don't care if they hurt other people's feelings.
Amy: That's not true.
Sheldon: That sounds like us.

Penny: Just thinking about the day I met you and Leonard.
Sheldon: It was a Monday afternoon. You joined us for Indian food.
Penny: Can you believe it's been eight years?
Sheldon: And you're still eating our food.

Sheldon: I think it's safe to say you're not in love with me and I'm not in love with you. And psychology has once again proved itself the doofus of the sciences.

Sheldon: Do you want to say it?
Amy: Let's say it together.
Sheldon and Amy: We're getting a turtle!

Amy: Are you asking me to go to Mars with you?
Sheldon: I am. If I'm going to a barren, lifeless environment, where the chances of survival are slim to none, I want you there with me.

Sheldon: I'm so excited. And I just can't hide it.
Leonard: Oh. I'm about to lose control. And I think I like it.
Sheldon: What are you talking about?

Leonard: Okay, fine. Sheldon, may I please visit your fort?
Sheldon: I want to say no, but it's too glorious. Get in here!

Sheldon: Well, I'll give you three guesses why I'm so irritated.
Howard: Something happened different from the way you wanted it.
Sheldon: I guess news travels fast.

Amy: Amazing.
Sheldon: I know. This isn't the printout. This is my real face.

Sheldon: Very well. I will agree to a family-friendly, G-rated, boy/girl sleepover.
Amy: PG. Some scenes may be too intense for younger viewers.
Sheldon: G-rated with a warning for families with babies and toddlers.
Amy: You got yourself a sleepover.

Amy: Sheldon, do you understand the irony of your fixation on a man with super speed, while after five years all I can get out of you is a distracted make-out session on a couch?
Sheldon: Irony's not really my strong suit.

Sheldon: What happened?
Penny: Your buddy got mugged by some baby farm animals.
Sheldon: Been there.