Howard: I've been at this lab for three years, you've never came by to say hello.
Sheldon: Well, up until now I've had better things to do. So, what are we making today?
Howard: A small payload support structure for a European science experimental package that's going up on the next space shuttle.
Sheldon: Really, how does it work?
Howard: When this is done, it will be attached to the payload bay, and the sensor apparatus will rest on it.
Sheldon: Uh, huh. So it's a shelf?
Howard: No, you don't understand, during acceleration it needs to stay perfectly level and provide ... yeah, okay, it's a shelf.

Howard: Sheldon.
Sheldon: Yes.
Howard: Go away.
Sheldon: Did Leonard tell you to say that?
Howard: No, I thought of it all by myself.
Sheldon: Huh. It can't be a coincidence. There must be some causal link I'm missing.

Raj: Go away!
Sheldon: Curiouser and curiouser.

Sheldon: Hey, Howard. You're a Jew. If there was another wailing wall, exactly like the one in Jerusalem, but close to taco stands and cheap prescription drugs, would you still be able to wail at it?

Dr. Gablehauser: Mr Kim was not only the valedictorian at Stamford University, he is also the youngest recipient of the prestigious Stephenson Award.
Sheldon: Youngest till the cyborgs rise up!

Sheldon: Anyway, the housekeeper in the faculty residence didn't speak any English. When I finally managed to convince her I was sick, she said, "Machtest du ein Darm sputum?"
Penny: What does that mean?
Sheldon: Based on what happened next, I assume it means, "Would you like an enema?"

Sheldon: Checkmate.
Leonard: Oh, again?
Sheldon: Obviously, you're not suited for three dimensional chess. Perhaps three dimensional Candy Land would be more your speed.
Leonard: Just reset the board!
Sheldon: It must be humbling to suck on so many levels.

Sheldon: Clearly febrile delirium is setting in. Please bring me some soup while I still understand what a spoon is for.

Sheldon: What kind of sick?
Penny: Oh, the flu, I guess.
Sheldon: I don't need you to guess, I need you to know. Now, when did the symptoms first appear?
Penny: Maybe Friday!
Sheldon: Friday! Was that morning or afternoon?
Penny: I don't--
Sheldon: Think, woman! Who blew their nose and when?

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: (blows nose into tissue, shows family sitting at nearby table) Would you call that moss green or forest green?

Leonard: Sheldon, relax. She doesn't have any symptoms, I'm sure she's not contagious.
Sheldon: Oh, please. If influenza was only contagious after symptoms appear it would have died out thousands of years ago. Somewhere between tool-using and cave-painting, Homo habilis would have figured out to kill the guy with the runny nose.

Leonard: What the hell are you doing?
Sheldon: I'm making petri dishes to grow throat cultures.
Leonard: With lime jello?
Sheldon: I need a growth medium, and someone polished off the apricot yogurt. Here, swab my throat.

Sheldon: Well, as I predicted, I am sick. My fever has been tracking up exponentially since 2am, and I am producing sputum at an alarming rate.
Leonard: No kidding?
Sheldon: No. Not only that, it has shifted from clear to milky green.
Leonard: Alright, well, get some rest and drink plenty of fluids.
Sheldon: What else would I drink? Gasses? Solids? Ionised plasma?

Penny: Sheldon, what are you doing here?
Sheldon: I'm sick, thank you very much.
Penny: How could you have gotten it from me? I'm not sick.
Sheldon: You're a carrier. All these people here are doomed. You're doomed!