Howard: Sheldon, if you were a robot, and I knew and you didn't, would you want me to tell you?
Sheldon: That depends. When I learn that I'm a robot, will I be able to handle it?
Howard: Maybe, although the history of science fiction is not on your side.
Sheldon: Uh, let me ask you this: when I learn that I'm a robot, would I be bound by Asimov's Three Laws of Robotics?
Raj: You might be bound by them right now.
Howard: That's true. Have you ever harmed a human being, or, through inaction, allowed a human being to come to harm?
Sheldon: Of course not.
Raj: Have you ever harmed yourself or allowed yourself to be harmed except in cases where a human being would've been endangered?
Sheldon: Well, no.
Howard: I smell robot.

Leonard [while Howard is teaching Sheldon Mandarin] Why are you learning Chinese?
Sheldon: I believe the Szechuan Palace has been passing off Orange Chicken as Tangerine Chicken, and I intend to confront them.
Leonard: If I were you, I'd be more concerned about what they're passing off as chicken.
[Penny comes in with an iPod in her hand.]
Penny: I need to use your window.
Leonard: Oh yeah, sure. Go ahead.
Penny: [opening the window and throwing the iPod out of it] Hey, jerkface! You forgot your iPod!
Leonard: [as Penny closes the window and starts to leave] What's going on?
Penny: Oh, I'll tell you what's going on: that stupid, self-centered bastard [her ex-boyfriend] wrote about our sex life in his blog! [going back to the window and reopening it] Drop dead, you stupid, self-centered bastard! [closing the window] Thank you. [leaves]
Sheldon: [after a short pause, wanting to go back to the Mandarin lessons] Okay, where were we?
Howard: [going to the computer] Not now. I have a blog to find.

Leonard: [about the time machine] The lights flash, and the dish spins. You wanna try it?
Penny: No, I don't wanna try it! My God, you are grown men! How could you waste your lives with these stupid toys and costumes, and comic books, and-and... now that-that...
Sheldon: Again--time machine.
Penny: Oh, please, that's not a time machine. If anything, it looks like something Elton John would drive through the Everglades.
Sheldon: It only moves in time. It would be less than worthless in a swamp.
Penny: Pathetic! ALL of you, COMPLETELY pathetic!

Leonard: [in Penny's apartment in the middle of the night] Do you realize if Penny wakes up, there's no reasonable explanation to why we are here?
Sheldon: I just gave you a reasonable explanation.
Leonard: No, you gave me an explanation. Its reasonableness will be determined by a jury of your peers!
Sheldon: Don't be ridiculous. I have no peers.

Leonard: [seeing Sheldon trying to sit on the couch where Penny's head is] What are you doing?
Sheldon: Every Saturday since we've lived in this apartment, I have awakened at 6:15, poured myself a bowl of cereal, added a quarter-cup of 2% milk, sat on this end of this couch, turned on BBC America, and watched Doctor Who.
Leonard: Penny's still sleeping.
Sheldon: Every Saturday since we've lived in this apartment, I have awakened at 6:15, poured myself a bowl of cereal��
Leonard: You have a TV in your room. Why don't you just have breakfast in bed?
Sheldon: Because I am neither an invalid nor a woman celebrating Mother's Day.

Leonard: [To Kurt] A Homo habilis just discovering his opposable thumbs says what?
Kurt: [Confused] What?

Leonard: Are there any other honors that I've gotten that I don't know about? Did UPS drop off a Nobel Prize with my name on it?
Sheldon: Leonard, please don't take this the wrong way, but the day you win a Nobel Prize is the day I begin my research on the drag coefficient of tassels on flying carpets.
Raj: The only thing missing from that insult was yo mama!
Howard: I got one. Hey Leonard, yo mama's research methodology's so flawed...
Leonard: Shut up Howard! Sheldon, we have to do this.
Sheldon: No we don't. We have to take in nourishment, expel waste, and inhale enough oxygen to keep our cells from dying. Everything else is optional.

Leonard: Hello Leslie.
Leslie: Hi Leonard.
Leonard: I'd like to propose an experiment��
Leslie: Goggles, Leonard.
Leonard: Right. I would like to propose an experiment.
Leslie: Hang on. I'm trying to see how long it takes a 500-kilowatt oxygen iodine laser to heat up my Cup o' Noodles.
Leonard: I've done it. About two seconds, 2.6 for minestrone. Anyway, I was thinking more of a bio-social exploration with a neuro-chemical overlay.
Leslie: Wait, are you asking me out?
Leonard: I was going to characterize it as the modification of our colleague-slash-friendship paradigm with the addition of a date-like component, but we don't need to quibble over terminology.
Leslie: What sort of experiment?
Leonard: There's a generally accepted pattern in this area. I would pick you up. Take you to a restaurant. Then we would see a movie, probably a romantic comedy featuring the talents of Hugh Grant or Sandra Bullock.
Leslie: Interesting. And would you agree that the primary way we would evaluate either the success or failure of the date would be based on the biochemical reaction during the good night kiss?
Leonard: Heart rate, pheromones, et cetera. Yes.
Leslie: Why don't we just stipulate that the date goes well and move to the key variable?
Leonard: You mean kiss you now?
Leslie: Yes.
Leonard: Can you define the parameters of the kiss?
Leslie: Closed-mouth but romantic. Mint?

Leonard: My parents focused on celebrating achievements, and my being expelled from a birth canal was not considered one of them.
Penny: That's so silly.
Sheldon: It's actually based on very sound theories; his mother published a paper on it.
Penny: What was it called, I Hate My Son and That's Why He Can't Have Cake?
Sheldon: It was obviously very effective. Leonard grew up to become an experimental physicist. Perhaps if she also denied him Christmas, he'd be a little better at it.
Leonard: Thank you.
Howard: Well, I love birthdays: waking up to mom's special French Toast breakfast, wearing the birthday king crown, playing laser tag with all my friends...
Penny: Yeah! See? That's what kids should have!
Howard: Actually, that was last year...

Leonard: Sheldon, think this through. You're going to ask Howard to choose between sex and Halo.
Sheldon: No, I'm going to ask him to choose between sex and Halo 3. As far as I know sex has not been upgraded to include high-def graphics and enhanced weapons systems.
Leonard: You're right, all sex has is nudity, orgasms and human contact.
Sheldon: My point.

Leonard: So, how do you two know each other?
Missy: Oh, he once spent nine months with my legs wrapped around his head.
Leonard: Excuse me?
Sheldon: She's my twin sister. She thinks she's funny, but frankly, I've never been able to see it.
Missy: That's because you have no measurable sense of humor, Shelly.
Sheldon: How exactly would one measure a sense of humor? A 'humormometer'?

Leonard: What did Penny mean, "you'd make a cute couple"?
Sheldon: Well, I assume she meant that the two of you together would constitute a couple that others might consider cute. An alternate, though somewhat less likely interpretation is that you could manufacture one. As in, "Oh, look, Leonard and Leslie made Mr. and Mrs. Goldfarb! Aren't they adorable?"
Leonard: If Penny didn't know that Leslie had already turned me down, then that would unambiguously mean that she, Penny, thought I should ask her, Leslie, out, indicating that she, Penny, had no interest in me asking her, Penny, out; but because she did know that I had asked Leslie out, and that she, Leslie, had turned me down, then she, Penny, could be offering me consolation - "That's too bad, you would have made a cute couple..." - while thinking, "good, Leonard remains available."
Sheldon: You're a lucky man, Leonard.
Leonard: How so?
Sheldon: You're talking to one of the three men in the Western Hemisphere capable of following that train of thought.
Leonard: Well, what do you think?
Sheldon: I said I could follow it, I didn't say I cared.

Leslie: Hello, Sheldon.
Sheldon: [looks terrified] Leslie Winkle!
Leslie: Yeah, Leslie Winkle! The answer to the question, "Who made Sheldon Cooper cry like a little girl?".
Sheldon: Yes, well, I'm polymerized tree sap and you're an inorganic adhesive, so whatever verbal projectile you launch in my direction is reflected off of me, returns on its original trajectory and adheres to you.
Leslie: [sarcastically] Ooooh...ouch.

Mrs. Cooper: [in trying to get Sheldon to go apologize to his boss Dr. Gablehauzer] Now listen here, Sheldon, I've been telling you since you were five years old, it's okay to be smarter than everyone else, but you can't go around pointing it out!
Sheldon: Why?
Mrs. Cooper: [sternly] Because other people don't like it!! Remember all the ass-kickings you used to get from the neighbor kids? Are you ready? Get your shoes, shirt and let's shove off!
Sheldon: [in a defeated tone of voice] There wouldn't have been any ass-kickings if that stupid death-ray would've worked.

Penny: [on phone] How about this: you keep him there a little longer, and when you get to the party, I'll point out which of my friends are easy.
Howard: [long pause] Don't toy with me, woman.
Penny: I've got a hot former fat girl with no self-esteem, I got a girl who punishes her father by sleeping around, and an alcoholic who's two tequila shots away from letting you wear her like a hat.
Howard: Thy will be done. [Hangs up, takes out granola bar with peanuts, to which he is allergic, and looks to his crotch] I'm doing this for you, little buddy.