"Sheldon: Uh Penny. That's where I sit.
Penny: Sit next to me.
Sheldon: ...no. I sit there.
Penny: What's the difference?
Sheldon: What's the difference?!
Leonard: Here we go.
Sheldon: In the winter, that seat is close enough to the radiator to remain warm and yet not so close as to cause perspiration. In the summer it is caught between a cross-breeze created by opening windows there and there. It faces the television at an angle that is neither direct thus discouraging conversation nor so far wide to create a paralex distortion. I could go on but, I think I've made my point."
"Sheldon Cooper: Hello, Penny.
Penny: Hello, Sheldon.
Sheldon Cooper: You're in my spot.
Penny: Are you planning on sitting here?
Sheldon Cooper: No, I'm going to the comic book store.
Penny: Then, what difference does it make?
Sheldon Cooper: What difference does it make?
Leonard Hofstadter: Here we go.
Sheldon Cooper: That is my spot, in an every changing world, it is a single point of consistency. If my life were expressed as a function on a four dimensional Cartesian coordinate system, that spot, from the moment I first sat on it, would be 0-0-0-0.
Penny: [blank star] What?
Leonard Hofstadter: Don't sit in his spot.
"Sheldon: Yes, in 1917 when Albert Einstein established the theoretic foundation for the laser in his paper "Zur Quantentheorie der Strahlung," his fondest hope was that the resultant device be bitchin'."
"Sheldon: That's not an apology; that's simply an acknowledgment that I was right.
Leonard: Okay, I'm sorry.
Sheldon: There you go."
"Leonard: What am I doing in your spam folder?
Sheldon: I put you there after you forwarded me a picture of a cat playing the piano entitled, "this is funny."
"Dr. Plimpton: What if there's a disaster that destroys all of the USB ports?
Sheldon: Then there's really no reason to live, is there?"
"Sheldon: It was a lot of work to accommodate you in my life. I'd hate to think that effort to be in vain."
"Sheldon: This is for you
Penny: Ice cream?
Sheldon: I've been familiarizing myself with female emotional crises by studying the comic strip, "Cathy." when she's upset she says, "ack" and eats ice cream.
Sheldon: If you were a cat, I would have brought you lasagna."
"Sheldon: Why did the chicken cross the mobius strip? To get to the same side."
"Leonard: What, to you, is a large crowd?
Sheldon: Any group big enough to trample me to death. General rule of thumb is 36 adults or 70 children."
"Sheldon: I can't give a speech.
Wolowitz: No, you're mistaken. You give speeches all the time. What you can't do is shut up.
Raj: Before the movie, you did twenty minutes on why guacamole turns brown. It turned brown while you were talking."
"Wolowitz: Why do you have all of these unopened paychecks in your desk?
Sheldon: Because most of the things I'm planning to buy haven't been invented yet."
"Sheldon: I believe you know why I'm here.
Penny: I always figured it was to study us, discover our weaknesses, and report back to your alien overlords."
"Sheldon: Do you recognize this?
Leonard: Not the roommate agreement!
Sheldon: Indeed, the roommate agreement. I call your attention to the friendship rider in Appendix C: Future Commitments, Number 37. In the event one friend is ever invited to visit the Large Haldron Collider, now under construction in Switzerland, he shall invite the other friend to accompany him.
Leonard: For god's sake!
Penny: You actually put that in an agreement?
Leonard: We also put in what happens if one of us gets a MacArthur grant, or if one of us gets super powers, or if one of us turns into a zombie.
Sheldon: He can't kill me, even if I turned.
Penny: Ts there anything in there if one of you gets a girlfriend?
Sheldon: No, that seemed a little far fetched."
"Sheldon: It's a bust of Sir Isaac Newton.
Penny: Oh sure, sure. Very Christmasy.
Sheldon: Well, excuse me, it's much more Christmasy than anything you put on the tree.
Leonard: Here we go...
Sheldon: December 25th, 1642. Julian calendar. Sir Issac Newton is born. Jesus, however, was actually born in the summer. His birthday was moved to coincide with the traditional pagan holiday that celebrates the winter solstice with lit fires and slaughtered guts, which frankly sounds like more fun than twelve hours of Church with my mother, followed by fruit cake."
"Leonard: The more the merrier.
Sheldon: That's a false equivalency, more does not equal merry. If there were two thousand people in this apartment, would we be celebrating? No, we'd be suffocating."
"Raj: No, no, no, no, that rate is much too low for what you'd expect from this collision. Do you understand we're taking about dark matter colliding in outer space?
Sheldon: Yes, of course I understand, and who are you to tell me about outer space?
Raj: Well, I am the astrophysicist! Astro means space!
Sheldon: Astro means star.
Raj: Okay, let me just tell you, if we were having this argument in my native language, I'd be kicking your butt!
Sheldon: English is your native language! (...)
Leonard: I've always been a little confused abut this -- why don't Hindus eat beef?
Raj: We believe cows are gods.
Sheldon: Not technically. In Hinduism cattle are thought to be like gods.
Raj: Do not tell me about my own culture Sheldon! In the mood I'm in I'll take you out, I swear to cow!"
"Sheldon: Hello, Penny. I realize that you're currently at the mercy of your primitive biological urges, but as you have an entire lifetime of poor decisions ahead of you, may I interrupt this one."
"Sheldon: You have to check your messages, Leonard! Leaving a message is one-half of a social contract, which is completed by the checking of the message. If that contract breaks down, then all social contracts break down and we descend into anarchy.
Leonard: It must be hell inside your head.
Sheldon: At times."
"Sheldon: You're probably thinking, "the comic book store, on a Thursday? Why I've fallen down the rabbit hole and into a land of madness." What you have failed to take into account, Penny, is that this is "Anything Can Happen Thursday"
"Sheldon: I'm a physicist. I have a working knowledge of the entire universe and everything it contains
Penny: Who's Radiohead?
Sheldon [after twitching for a minute]: I have a working knowledge of the important things"
Leonard: 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.
"Wil Wheaton: Did he just say "Revenge is a dish best served cold" in Klingon?
Stuart: I believe he did, yes.
Wil Wheaton: What is wrong with him?
Stuart: Everyone's got a different theory."
The Big Bang Theory
"Sheldon: If outside is so good, why has mankind spent thousands of years trying to perfect inside?"