Penny: So, you know, isn't there maybe some way you and Sheldon could compromise on this whole presentation thing?
Leonard: No. Scientists do not compromise. Our minds are trained to synthesize facts and come to inarguable conclusions. Not to mention Sheldon is bat-crap crazy

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 co-efficient of tassels on flying carpets

Leonard [watching their fight on YouTube]: Oh, geez, does this suit really look that bad?
Sheldon: Forget your suit. Look at my arms flailing. I'm like a flamingo on Ritalin

Leonard: Sheldon, why is this letter in the trash?
Sheldon: Well, there's always the possibility that a trash can spontaneously formed around the letter, but Occam's Razor would suggest that someone threw it out

Leonard: You are not Isaac Newton.
Sheldon: No, no, that's true. Gravity would have been apparent to me without the apple

Leonard [referring to Sheldon singing]: What got into him?
Penny: Oh, just a couple virgin Cuba Libres that turned out to be kinda slutty

Leonard: Look at the bright side. [Lalita] might turn out to be a nice, beautiful girl.
Raj: Great, then we'll get married, I won't be able to talk to her, and we'll spend the rest of our lives in total silence.
Wolowitz: Worked for my parents

Penny [to Raj about Lalita]: No one can make you get married. Why don't you just meet this girl and see what happens?
Raj: Haven't you been listening to me? I cannot talk to women!
Leonard: Um, Raj?
Wolowitz: No, no, let's see how long it takes him

Sheldon: When I was a little boy and got sick, which was most of the time, my mother would read [The Monkey and the Princess] to me. It's about an Indian princess who befriends a monkey who was mocked by all the other monkeys because he was different. For some reason I related to it quite strongly.
Penny: I know the reason.
Leonard: We all know the reason

Penny: I need some guinea pigs.
Sheldon: Okay, there's a lab animal supply company in Reseda you can try. But if your research is going to have human applications, may I suggest white mice? Their brain chemistry is far closer to ours.
Penny: I swear to God, Sheldon, one day I'm going to get the hang of talking to you.
Leonard: His mom's been saying that for years

Leonard: Do you really need the Honorary Justice League of America Membership card?
Sheldon: It's been in every wallet I owned since I was five.
Leonard: Why?
Sheldon: It says keep this on your person at all times. It's right here under Batman's signature.

Penny: Hey, if you guys need a fourth, I'll play.
Leonard: Great idea!
Sheldon: Uh, no. The wheel was a great idea. Relativity was a great idea. This is a notion, and a rather sucky one at that.
Penny: Why?!
Sheldon: Why? Oho, Penny, Penny, Penny.
Penny: Oho, what, what, what? [picks up controller]
Sheldon: This is a complex battle simulation with a steep learning curve. There are a myriad of weapons, vehicles, and strategies to master, and not to mention an extremely intricate back story.
Penny: Oh, cool! Whose head did I just blow off?
Sheldon: Mine.

TBBT Quotes

Sheldon: I recently read that during World War Two, Joseph Stalin had a research program to create supersoldiers by having women impregnated by gorillas.
Howard: What a sick use of science.
Raj: Hey, as long as the baby's healthy.
Amy: I wonder if Stalin considered any other animals.
Leonard: Hippos are the deadliest creature. A half-human, half-hippo soldier would be pretty badass.
Howard: Yes, but when they're hungry-hungry, you can stop them with marbles.
Sheldon: Yeah, the correct animal for interspecies supersolider is koala. You would wind up with an army so cute it couldn't be attacked.

Raj: Well, to paraphrase Shakespeare: It's better to have loved and lost than to stay home every night and download increasingly shameful pornography.
Penny: Oh... you poor baby.
Raj: What's wrong with me, Penny?
Penny: Nothing, nothing. You know, if we weren't friends - and you hadn't brought up that creepy pornography story - I'd be on you like the speed of light squared on matter to make energy.
Raj: Hey, you totally got that right. E = MC squared.
Penny: I listen. I have no idea what it means, but I listen.