Leonard: You put moths in my food!?
Sheldon: For science.

Leonard: You know what happens when you yawn in public...
Sheldon: Everyone will see my oddly shaped uvela.

Sheldon: I want you to know that I'm genuinely concerned about your well-being.
Leonard: Thank you.
Sheldon: You're welcome. But it's still no reason to have your feet in my spot.

Leonard: Have you considered telling her your feelings?
Sheldon: Leonard, I'm a physicist, not a hippie.
Leonard: Well let me see if I can explain your situation using physics. What would you be if you were attached to another object by an incline plane, wrapped helicly around an axis.
Sheldon: Screwed.
Leonard: There you go.

Leonard: How can you have a girlfriend you can't even speak to women?
Raj: Two words: deaf chick. It doesn't matter if i can't talk cause she can't hear me.
Leonard: What?
Raj: That's what she said.

If they took all the money trying to make a decent Hulk movie, they could probably just make an actual Hulk.

Sheldon: Why on earth are you telling me all this?
Leonard: Sometimes you movements are so lifelike I forget you're not a real boy.

Leonard: Why would you want a glow-in-the-dark ant farm?
Sheldon: They do some of their best work at night.

Wolowitz: I love watching Raj and Sheldon try to work together.
Leonard: Yeah, it's like if Alien and Predator decided to go partners in a Jamba Juice.

Leonard: ...and when she died, they ate her.
Sheldon: You don't have to sell me on cats, I'm already a fan!

Leonard: So, this is nice. First time we've all gotten together to eat.
Amy (to Sheldon): You're right. He's a festival of humdrum chitchat.
Leonard: Okay, that's all I got. Howard, you're up.
Wolowitz: Um, tell us about your work, Amy.
Amy: I doubt you'd understand. Sheldon tells me you only have a master's degree.
Wolowitz: Raj, do you have any questions for Amy?

Leonard: Did you guys see the paper in the American Physics Journal on supersolids? It's pretty interesting. This guy's working from a hypothesis which ...
Raj: Spoiler alert! Spoiler alert!
Leonard: What?
Raj: Don't ruin it for me, man! I printed out a PDF to read on the potty.

TBBT Quotes

Penny: Hey, Sheldon, did you change your Wi-Fi password again?
Sheldon: Yes, it's "Penny, get your own Wi-Fi." No spaces.

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