Leonard: Refresh my memory. Why didn't I just put you in the trunk?
Sheldon: Because I called shotgun, remember?

Leonard: Why a turtle?
Sheldon: After much deliberation, we've determined that a turtle is the ideal pet. They don't shed fur. They don't make noise.
Amy: For Halloween, we can dress him as a cobble stone.
Sheldon: And, if he ever goes beserk, I know I can out run him. Coincidentally that's also why I chose you as a roommate.

Amy: We could also be the first people to procreate on Mars.
Sheldon: You just can't keep it in your space pants, can you?

Sheldon: It's an earthquake. I knew it.
Penny: Sheldon, it's just a little tremor.
Sheldon: A little tremor that turns routine sinus surgery into a frontal lobotomy.

Bernadette: Sheldon, when was the last time you got any sleep?
Sheldon: I don't know. 2 or 3 days. Not important. I don't need sleep, I need answers. I need to determine where in this swamp of unbalanced formulas squatteth the toad of truth.
Penny: Toad of truth? Is that a physics thing?
Leonard: No, that's a crazy thing.

Koothrappali: Oh, great. No Superman, no Wonder Woman? All we've got is a skinny Flash, an Indian Aquaman, a near-sighted Green Lantern, and a teeny, tiny Dark Knight.
Sheldon: Obviously, we're no longer a Justice League. We have no choice but to switch to our Muppet Baby costumes.
Koothrappali: Ooh, I call Kermit.
Sheldon: I'm Kermit. You're Scooter.
Koothrappali: Oh, man. Scooter sucks. He's the Aquaman of the Muppet Babies.

Leonard: You wrote a paper on my idea?
Sheldon: I wrote a paper on our idea.
Leonard: When did my idea become our idea?
Sheldon: When I mixed it with Sheldony goodness and cooked it in the Easy Bake oven of my mind.

Sheldon: Pee for Houston, pee for Austin.
Pee for the state my heart got lost in.
And shake twice for Texas.

Sheldon: [jumps out of the sofa] Bazinga, punk. Now we're even!

Sheldon: Hello, Amy Farrah Fowler. I'm sorry to inform you that you've been taken in by unsupportable mathematics designed to prey upon the gullible and the lonely. Additionally, I am being blackmailed with a hidden dirty sock.
Amy: If that was slang, I'm unfamiliar with it. If it was literal, I share your aversion to soiled hosiery.

Leonard: Sheldon, you are not sick. This is, but you are not.
Sheldon: We have no idea what pathogens Typhoid Penny has introduced into our environment. And having never been to Nebraska, I'm certain I have no corn-husking antibodies.
Leonard: Sheldon, don't you think you're overreacting?
Sheldon: When I'm lying comatose in a hospital relying on inferior minds to cure me, these gelatin cultures and my accompanying notes will give them a fighting chance.
*Sheldon holds a Q-tip toward his mouth for Leonard to swab*

Sheldon: "See you in hell Sheldon"? The most frightening thing about that is the missing comma.

Sheldon: Boy, oh, boy. This vacation is off to a wonderful start. The smell of formaldehyde, the whir of the centrifuge, the distant chatter of lab animals being dispatched for dissection. Mm, I can already feel my cares just melting away.
Amy: I'm excited to work with my boyfriend. It's going to be romantic.
Sheldon: Way to kill the mood.

Sheldon: I'm baaaaaaaaaaaaaaaack.

Sheldon: I would point out that I am at the top of my profession, while you preside over the kiddie table of yours.