Leonard: It comes with paints and it's kind of creative and artistic.
Penny: Okay, did you go to the dirty store, or Michaels?

Leonard: I'm telling you, you can't create love in a few hours. Right?
Penny: Careful. You're poking at the whole foundation of The Bachelor.

Amy: I just read about an experiment designed to see if you can make two people fall in love in a matter of hours.
Leonard: That doesn't sound right. My research has shown that it takes three to five years of shameless begging.

Let's have a toast. To Mrs. Wolowitz. A loving mother ... to all of us. We'll miss you.

Sheldon: I didn't care for her yelling, but now that I'm not going to hear it again, I'm sad.
Leonard: If you want, I can yell at you later.
Sheldon: It won't be as good.

Nathan Fillion: How about a guy who looks like Nathan Fillion, but a little more annoyed than Nathan Fillion usually is?
Leonard: What do you think?
Raj: Aww. That's good enough for Facebook.

Raj: The guy who plays Jon Snow was a jerk and we still watch Game of Thrones.
Leonard: He was a jerk because you rear-ended him.
Raj: I was distracted. It's weird seeing a member of the Night's Watch with kayak strapped to his car.

Leonard: Stephen Hawking liked our paper. Said the premise is intriguing.
Sheldon: Good to see you again, Mr. Stephen-Hawking- Liked-Our-Paper.
Leonard: And you as well, Mr. Our-Premise-Is-Intriguing.
Howard: How do you do, Mr. I'll- Admit-That's-Pretty-Cool?
Raj: Yeah, you keep setting me up for failure.

Sheldon: Professor Hawking?
Professor Hawking: Oh, brother, you should see the look on your faces.
Leonard: You really didn't like our paper?
Professor Hawking: I like your paper very much. The premise is intriguing.
Sheldon: Then why are you attacking us?
Professor Hawking: If you were sitting in a chair for 40 years, you'd get bored, too. Anyway, got to go. I promised to help the neighbor kid with his math homework. Ciao.

Leonard: Uh, another one says, "The concept shows some real out-of-the-box thinking".
Sheldon: Do you hear that, Mr. Out-Of-The?
Leonard: I do, indeed, Mr. Box-Thinking.

Leonard: You're sure it's good?
Sheldon: My name is right on there with yours. That is a surefire
mark of quality. That might as well say "Directed by Joss Whedon".
Leonard: Okay, partner, let's do it.

Leonard: You wrote a paper on my idea?
Sheldon: I wrote a paper on our idea.
Leonard: When did my idea become our idea?
Sheldon: When I mixed it with Sheldony goodness and cooked it in the Easy-Bake Oven of my mind.
Leonard: This is good. Our idea is really good.
Sheldon: Well, the light bulb in this oven is ridiculously bright.

TBBT Quotes

It's very simple. Scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and, as it always has, rock crushes scissors

Sheldon

Sheldon: Why do you have the Chinese character for "soup" tattooed on your right buttock?
Penny: It's not "soup," it's "courage."
Sheldon: No it isn't. But I suppose it does take courage to demonstrate that kind of commitment to soup.
Penny: How'd you see it? You said you wouldn't look.
Sheldon: Sorry. As I told you, the hero always peeks.