Sheldon: Is the whip sound app contextually appropriate here?
Leonard: Uh, it is, but I think you might have waited too long for it to be funny.
[whip cracks]
Leonard: [Everyone laughs] I was wrong; it was still funny.

Leonard: We're always the good guys. In D&D, we're lawful good. In City of Heroes, we're the heroes. In Grand Theft Auto, we pay the prostitutes promptly and never hit them with a bat.
Sheldon: Those women are prostitutes? You said they were raising money for stem cell research.

Sorry, Stallion. You're weird friend, Giraffe, is here.

Penny

Howard: Now, I downloaded an app that might be helpful in this situation.
[whip cracks]
Sheldon: You're right. I'm smart as a whip. I should be able to figure this out.

Leonard: We'll miss you Sheldon.
Sheldon: Yeah, well, who wants to spend the whole weekend, running around a bunch of pretend planets, battling made up monsters? That's for babies.
Howard: Yeah, but it's got lightsabers.
Sheldon: Please, Amy! It's got lightsabers!

She's 93. She won't be disappointed for very long.

Penny: Please come home and let me cut your hair.
Sheldon: Amy what do you think?
Amy: There's not a hair on this body I wouldn't let this woman trim.

Penny: Where are you going?
Sheldon: Where ever the music takes me kitten.

Penny: Why did you get bongos?
Sheldon: Richard Feynman played bongos, I thought I would give that a try
Leonard: Richard Feynman was a physicist
Penny: It's three o'clock in the morning, I don't care if Richard Feynman was a purple leprechaun that lived in my butt!

I gotta run...[stops] but not with scissors, that would be unsafe.

Amy: What about Supercuts?
Sheldon: I tried it once; they cut men and women hair at the same time in the same room. It's like Sodom and Gomorrah with mousse.

Penny: I use to cut my brother's hair. I could do it for you
Sheldon: I know you mean well, offering the skills of the hill folk, but here in town we don't churn our own butter, we don't make dresses from gunny sacks, and sure-as-shootin don't get our hair cut by bottle blon..
Leonard: Sheldon be nice!

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.

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.