Sheldon: If I'm permitted to speak again, Dr. Sheldon Cooper for the win!

Sheldon: Yeah, I'm definitely going with colonoscopy.
Leonard: Okay, bye. (Off the phone) My mother's coming for a visit.
Howard: How about that, you were right.

(Sheldon smiles in a grotesque way).
Howard: Oh crap that's terrifying.

Leonard: OK, is everyone clear on the plan?
Howard: Yes, Koothrappali's going to wet himself, I'm gonna throw up, Sheldon's gonna run away and you're going to die. Shall we synchronize our watches?

Kurt: Where's your back up?
Leonard: I don't need back up, I have right on my side ... and I'm wearing cargo shorts under my pants.

Sheldon: Scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and as it always has, rock crushes scissors.

Howard: Maybe we should have your head notarized.

Sheldon: Studies are shown that performing tasks such as eating, talking on a cell phone or drinking coffee while driving reduces ones reaction time by the same factors as ounce of alcohol.

Leonard: How can 5 not be worse than 1?
Raj: Yeah, Star Trek 5 worse than 1.
Sheldon: Okay, first of all that is a comparison of quality not intensity. Secondly, Star Trek 1 is orders of magnitude worse than Star Trek 5.
Raj: Are you joking? Star Trek 5 is the standard against which all badness is measured.

Sheldon: This is an auspicious moment, like Robert Oppenhiemer or Neil Armstrong, we need the appropriate words to mark this historic scientific event.
Rajesh: How about, die toaster, die!
Leonard: That'll do it!

Howard: Behold the Mobile Omni-Directional Neutralization and Termination Eradicator! Or...
Leonard, Sheldon, Howard, Raj: Monte.

Sheldon: Is it wrong to say I love our killer robot?
Rajesh: As with my father I both love and fear it.

Sheldon: That's awfully sticky.

Leonard: Don't you think if a woman was living with me I'd be the first one to know about it?
Penny: Oh, sweetie, you'd be the last one to know about it.

Leonard: No, absolutely not.
Sheldon: It's not a big deal.We have latex gloves.
Leonard: I don't care what the symptoms are. My girlfriend is not going to give you a prostate exam.