Penny: Alright, Sheldon, let's just calm down and we'll call the building manager, he'll come open your door, you just eat your dinner here while you're waiting.
Sheldon: Eat? My dinner? In your apartment?
Penny: Yeah, why not?
Sheldon: Sure, why not? And after the sun's down we can all pile in my pick-up and go skinny-dipping down at the creek. 'cause today's the day to stop making sense.

Sheldon: That's an inexact parallel. You and Leonard can always return to being friends, whereas I can never return to a state in which Wolowitz has not bested me like Mrs. Riley's chicken.
Penny: What's Mrs. Riley's chicken?
Sheldon: A chicken that was owned by Mrs. Riley.
Penny: Okay, forget the chicken.
Sheldon: Well, I wish I could.

Sheldon: Thanks, Dad. We're gonna give them hell.

Sheldon: I'm looking over my text correspondence with Beverly and I don't see anything that would have given her offense. Nothing's ambiguous, I spell everything out. Including "laugh out loud" and "what's the fracas?"

Amy: Oh. That's me. Hello? Yes, this is Dr. Fowler. I see. Okay, thank you. We won.
Penny: Congratulations!
Leonard: Oh, my God!
Sheldon: We did it.
Amy: I know. Can you believe it?
Sheldon: That's a good point. What if I'm dreaming? [Leonard slaps Sheldon] We won the Nobel Prize!

Sheldon: Yes, since their relationship became carnal, Penny has updated his designated term of endearment, distinguishing him from those she calls 'sweetie,' usually as an attempt to soften a thinly-veiled insult.
Penny: You're boring people, sweetie.
Sheldon: Although sometimes, she omits the veil entirely.

Sheldon: I'm sorry but I'm not going to watch the Clone Wars TV Series until I've seen the Clone Wars movie. I prefer to let George Lucas disappoint me in the order he intended.

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.

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

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: If I could I would, but I can't so I shan't.

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

Sheldon: I should've brought an umbrella.
Leonard: What for? It's not going to rain.
Sheldon: I know that, but with skin as fair as mine, moon burn is a real possibility.
Howard: That's a bazinga, right?
Sheldon: One of my best, don't you think?

Sheldon: Perhaps your talk of my sexual prowess renewed her faith in love.

Sheldon: I'm baaaaaaaaaaaaaaaack.