The Big Bang Theory Season 1 Episode 1

Leonard: At least I didn't have to invent 26 dimensions just to make the math come out.
Sheldon: I didn't invent them, they are there!
Leonard: In what universe?
Sheldon: In all of them, that's the point.

Leonard: We need to widen our circle.
Sheldon: I have a very wide circle. I have 212 friends on MySpace.
Leonard: Yes, and you've never met one of them.
Sheldon: That's the beauty of it.

Penny: I'm a Sagittarius, which probably tells you way more than you need to know.
Sheldon: Yes, it tells us that you participate in the mass cultural delusion that the sun's apparent position relative to arbitrarily defined constellations at the time of your birth somehow affects your personality.
Penny: (puzzled) Participate in the what?

Penny: (after seeing Leonard and Sheldon pantsed) I'm so sorry. I really thought if you guys went instead of me, he wouldn't be such an ass.
Leonard: No, it was a valid hypothesis.
Sheldon: That, "was a valid hypo"—what is happening to you?

(at the high-IQ sperm bank, discussing committing genetic fraud)
Sheldon: What if she ends up with a toddler who doesn't know if he should use an integral or a differential to solve for the area under a curve?
Leonard: I'm sure she'll still love him.
Sheldon: I wouldn't.

Leonard: Our babies would be smart and beautiful.
Sheldon: Not to mention imaginary.

Howard: (upon seeing Penny) Enchante, Mademoiselle. Howard Wolowitz, Caltech Department of Applied Physics. You may be familiar with some of my work. It's currently orbiting Jupiter's largest moon, taking high-resolution digital photographs.
Penny: (a little confused) Penny. I work at the Cheesecake Factory.

Sheldon: Are you still mad about the sperm bank?
Leonard: No!
Sheldon: Do you want to hear an interesting thing about stairs?
Leonard: Not really.
Sheldon: If the height of a single step is off by as little as two millimeters most people will trip.
Leonard: I don't care—two millimeters?! That doesn't seem right.
Sheldon: No, it's true! I did a series of experiments when I was twelve; my father broke his clavicle.

Penny: I'm a vegetarian. Well, except for fish, and the occasional steak. I love steak!
Sheldon: Well, that's interesting. Leonard can't process corn.

(Althea is having trouble with a crossword puzzle; Leonard takes a look at it)
Leonard: One across is Aegean, eight down is Nabokov, twenty-six across is MCM, fourteen down is, move your finger... (Althea moves her finger) phylum, which makes fourteen across Port-au-Prince. (Althea gives him a look) See, Papa Doc's capital idea, that's Port-au-Prince, Haiti.

(as they walk up the stairs after being "pantsed")
Leonard: Sheldon, I am so sorry I dragged you through this.
Sheldon: It's ok. It wasn't my first pantsing, and it won't be my last.
Leonard: But you were right about my motives. I was hoping to establish a relationship with Penny that might have someday led to sex.
Sheldon: Well, you got me out of my pants.

Penny: And on top of everything else, I'm all gross from moving. My stupid shower doesn't even work.
Leonard: Our shower works.
Penny: Really? Would it be totally weird if I used it?
Sheldon: Yes.
Leonard: No!
Sheldon: No?
Leonard: No.
Sheldon: No.

(on their way to pick up the TV from Penny's ex-boyfriend)
Sheldon: And why can't she get her own TV?
Leonard: Come on, you know how it is with break-ups.
Sheldon: No, I don't and neither do you.
Leonard: But I -- I broke up with Joyce Kim.
Sheldon: You did not break-up with Joyce Kim, she defected to North Korea.
Leonard: To mend her broken heart.