Sheldon: Sherlock Holmes always says when you eliminate the impossible, whatever remains, however improbable, must be the truth. Now, have you tried doing that?
Officer Hernandez: Nope.
Sheldon: Well, maybe you should. There's lots of books called Sherlock Holmes and there's no books called Officer Hernandez.

Sheldon: Wow, pouting and running away actually worked. I must say that may not be a lesson you want to reinforce with me.

Leonard: It wasn't until his twenty-first birthday that 1955 Biff placed his first bet.
Sheldon: Wow wow wow. Is 'placed' right?
Leonard: What do you mean?
Sheldon: Is 'placed' the right tense for something that would have happened in the future of a past that was affected by something from the future?
Leonard: 'Had will have placed'?
Sheldon: That's my boy.

Leonard: What are we going to do?
Sheldon: Perform the experiment immediately.
Leonard: I'd love to, but we need liquid helium and our shipment's on back order for a month.
Sheldon: A month? What? Are you kidding me? That would have been a good time for you to soften the blow.
Leonard: That shirt brings out the blue in your eyes.
Sheldon: Thank you. Aren't you sweet?

Sheldon: Dear Crazy Future Sheldon, you were driven mad by an earworm. Your mind, once your most trusted asset, is now a sack of parrots and monkeys. So I'm going to tell you everything you need to know. Uh, first, music is dangerous. The movie Footloose tried to warn us, but we wouldn't listen.

Leonard: Hey, did you ever think about the military applications for the guidance system?
Sheldon: Of course.
Leonard: Does it bother you?
Sheldon: No, it did at first. But then I talked it through with Frank and Alicia, and they really helped put things into perspective.
Leonard: Who are these people?
Sheldon: Leonard, friends are like toilet paper. It's good to have extras under the sink.

Leonard: I guess we'll just take [a TV cabinet] up [the stairs] ourselves.
Sheldon: We don't have a dolly, or lifting belts, or any measurable upper-body strength.
Leonard: We don't need strength. We're physicists. We are the intellectual descendants of Archimedes. Give me a fulcrum and a lever, and I can move the Earth. (Trying to move the box) It's just a matter of... I don't have this. I don't have this. I don't have it!
Sheldon: Archimedes would be so proud.

Sheldon: I believe the appropriate metaphor here involves a river of excrement and a Native American water vessel without any means of propulsion.

Wil Wheaton: You ready to bowl?
Sheldon: Oh, I'm ready. I don't know if Stuart told you what you are up against tonight, but before you stands the co-captain of the East Texas Christian Youth Holy Roller Bowling League Championship Team 7-12 year-old division. Also, Penny is pretty good.
Wheaton: Great, then it's on.
Sheldon (to himself): Foolish Wil Wheaton. It was never off.

Sheldon: I'm surprised you struck out with Penny. Apparently she's a big ol' five.

Sheldon: I don't know which arctic expedition you guys were on, but I thought it was a hoot and a half.

Sheldon: (Practising speaking Mandarin) Show me your citrus peels.
Penny: Sheldon?
*Sheldon freaks out in Chinese.*
Penny: I'm sorry. Look, do you have a second?
Sheldon: A second what? Pair of underwear?

Ramona: Didn't a great man once say, "Science demands nothing less than the fervent and unconditional dedication of our entire lives."?
Sheldon: He did.
Ramona: And who was that great man?
Sheldon: Me. Sorry, Leonard.
Leonard: Seriously? You're not coming?
Sheldon: You heard her. How can I argue with me?

Kripke: Well, as long as we're here, I might as well take a leak.
Sheldon: Kripke, you're in my spot.

Sheldon: That's no reason to cry. One cries because one is sad. For example, I cry because others are stupid, and that makes me sad.