Howard: Hope you don't mind, I told my girlfriend, Bernadette, she can join us for dinner.
Leonard: Sure, the more the merrier.
Sheldon: Wait, no. That's a false equivalency. More does not equal merry. If there was 2000 people in this apartment right now, would we be celebrating? No, we'd be suffocating.

Leonard: What's a dogapus?
Sheldon: A hybrid dog and octopus. Man's underwater best friend.
Leonard: There's someone working on that?
Sheldon: I was going to. I planned on giving it to myself for my 300th birthday.
Leonard: Wait a minute you hate dogs.
Sheldon: A dogapus can play fetch with eight balls; no one can hate that.

Sheldon: I assure you, you'll be sorry that you wasted your money on an iPod when Microsoft comes out with theirs.
Rajesh: Do you have an opinion about everything?
Sheldon: Yes.
Howard: And you just assume you're right?
Sheldon: It's not an assumption.

Amy: I've seen and talked to you more in the two days we've been broken up than in the last two months we were together.
Sheldon: Well, if you want to see less of me, maybe we should go out again.

Sheldon: I'm not Sheldon. I'm the Flash. And now I'm going to the Grand Canyon to scream in frustration. *takes two quick steps* I'm back.

Zack: You're inferring I'm stupid.
Sheldon: That's not correct. We implied you're stupid, you then inferred it.

Sheldon: Do you want to hear an interesting thing about stairs?
Leonard: Not really!
Sheldon: If the height of a step is off by as little as two millimeters, most people will trip.
Leonard: I don't care. 2 millime--? That doesn't seem right.
Sheldon: It's true. I did a series of experiments when I was 12. My father broke his clavicle.
Leonard: Is that why they sent you to boarding school?
Sheldon: No. That was the result of my work with lasers.

Sheldon: Good morning everyone and welcome to "Science and Society". I'm Dr. Sheldon Cooper, BS, MS, MA, PhD and ScD. OMG, right?

Sheldon: I can't seem to get in touch with Amy. I tried e-mail, video chat, tweeting her, posting on her Facebook wall,texting her, nothing.
Leonard: Did you try calling her on the telephone?
Sheldon: The telephone. You know, Leonard, in your own simple way, you may be the wisest of us all.

Sheldon: Ah, memory impairment; the free prize at the bottom of every vodka bottle.

Sheldon: Who's ready to laugh? [Leonard groans] Okay. So Feynman, Einstein and Schrodinger walk into a bar. Feynman says, "It appears we're inside a joke." Einstein replies, "But only to an observer who saw us walk in simultaneously." To which Schrodinger says, "If someone's looking in the window, I'm leaving."
Leonard: [chuckles] That's actually funny.
Raj: You should send that to Jimmy Fallon.

Sheldon: You can't make a half sandwich. If it's not half of a whole sandwich, it's just a small sandwich.

Sheldon: I have a masters and two PhDs. I should not have to do this.

Sheldon: Oh Mario, if only I could control everyone the way I control you. Hop, you little plumber. Hop, hop hop!

Penny: Yes, I know men can't fly.
Sheldon: No, no let's assume that they can. Lois Lane is falling, accelerating at an initial rate of 32ft per second, per second. Superman swoops down to save her by reaching out two arms of steel. Ms. Lane, who is now traveling at approximately 120 miles per hour, hits them, and is immediately sliced into three equal pieces.
Leonard: Unless Superman matches her speed and decelerates.
Sheldon: In what space, sir, in what space? She's two feet above the ground. Frankly, if he really loved her, he'd let her hit the pavement. It would be a more merciful death.