Leonard: Hey, Amy, what brings you to our neck of the woods?
Amy: Your neurology department loaned me a culture of prions for my research on bovine spongiform encephalopathy.
Sheldon: She popped by to borrow a cup of mad cow disease.
Amy: It's hard to make degenerative brain maladies hilarious, and yet somehow you do it.

Howard: Can we get that off the table and change the subject?
Sheldon: Can we? Stand back while I turn this conversation into a conver-sensation.
Leonard: This time, it's your fault.
Sheldon: I have 100 alphabetized topics from "Artichoke, come on, people, it's just a giant thistle" to "ZZZ, the onamona-poetry of sleep".

Leonard: Amy, how long would it take for that mad cow disease to kill me?
Amy: I don't know, four or five years.
Leonard: No, it's not gonna do it.

Leonard: Leonard's coming down the home stretch. Come on, horsey, you can do this Damn. Come on, thigh muscles, you can do this. Yes, first place! I would have been a great jockey if I weren't too tall. And scared of horses.

Amy: Sheldon, what are you doing here?
Sheldon: You didn't respond to any of my electronic communications.
Amy: I wanted to be alone.
Sheldon: Would you like to talk about it? And keep in mind that no is a perfectly viable answer.

Amy: Sheldon, my world is crumbling around me.
Sheldon: Point of order. As you're in distress, it would be customary for me to offer you a hot beverage. But I'm a guest in your home, so it would be customary for you to offer me a beverage. How do you want to proceed vis-a-vis beverages?

Leonard: You didn't see me telling Kevin that you thought Cold Wars were only fought in Winter

Penny: Then I'll return the favor and I won't tell...
Laura: Laura-
Penny: Laura that half the dirty movies you own are animated.

Leonard: Oh, hey. You work the lunch shift?
Penny: Yeah. I've got eight pounds of salmon that's about to go bad. Do you know how to cook it?
Leonard: Not really.
Penny: Damn it. Should have liberated the iffy chicken.

Sheldon: [inside the apartment] Oh, dear Lord, get away from me, you monster!
Penny: [in the hallway] What is that about?
Leonard: Well, he's smart and crazy enough, he may have actually created a monster.

Penny: Oh, hey, if we hurry, we can make the new Jennifer Aniston movie.
Leonard: Oh, yeah, sure. There's also an amazing documentary about building a dam on river in South America.
Penny: Okay, but the Jennifer Aniston movie has Jennifer Aniston, and she's not building a dam.

Leonard: Does this sound familiar? I'd love to go shoe shopping with you. Hiking? It's great. It's two a.m., of course I want to go to Korea Town and sing karaoke with your friends. Who wouldn't?
Penny: Okay, we were going out. You were going to get sex anyway.
Leonard: Really? You would have slept with me after a three-hour documentary on dams?
Penny: No. No woman would.

Leonard: See? Now, that's the great thing. We're out as friends. This is not a date. Sex is off the table. So, let's go learn why hydroelectric power might not be the environmental bargain you think it is. Sorry. Spoiler alert.

Sheldon: This would go a lot faster if you put your trade school diploma to work and helped me set up this high frequency tone generator.
Howard: I have a Masters degree from M.I.T.
Sheldon: Yeah, but you've got a can-do attitude and that's what's important.

Sheldon: Age seven, a blood-thirsty chicken chases me up a tree. Age twelve, a magpie tries to steal the retainer out of my mouth. Age sixteen, a parrot in a pet store called me fat ass. Need I go on?
Raj: Yes, please. This is way better than the movie.