Sheldon: Can you sing "Soft Kitty"?
Penny: What?
Sheldon: My mom used to sing it to me when I was sick.
Penny: I'm sorry honey, I don't know it.
Sheldon: I’ll teach you. [Singing] Soft kitty, warm kitty, little ball of fur. Happy kitty, sleepy kitty, purr, purr, purr. Now you.

Penny: Yes, I will go out with you.
Leonard: Really?
Penny: Yeah. Why not? I mean, what do I have to lose?
Leonard: Yeah. That's the spirit

Wolowitz: You know, I'm really glad you decided to learn Mandarin.
Sheldon: Why?
Wolowitz: Once you're fluent, you'll have a billion more people to annoy instead of me

Penny: Leonard isn't the kind of guy I usually go out with.
Sheldon: Leonard isn't the kind of guy anyone usually goes out with

Leonard: I don't think I can go out with [Penny] tonight.
Sheldon: Then don't.
Leonard: Other people would say, "Why not?"
Sheldon: Other people might be interested

Leonard: Why are you learning Chinese?
Sheldon: I believe the Szechuan Palace has been passing off orange chicken as tangerine chicken, and I intend to confront them.
Leonard: If I were you, I'd be more concerned with what they're passing off as chicken

Leonard: What happened?
Penny: Well, I went over to Mike's to make up with him.
Leonard: Yeah. No, I know that part.
Penny: But he had already moved on.
Leonard: Already? That was quick.
Penny [crying]: That's what I said to the woman who had her legs wrapped around his neck!

Penny: I swear to God, I am done with guys like that. You know, macho with the perfect body and hair, and money.
Leonard: Yeah, that must get old quick

Raj: Hey, look, I found an iPod!
Wolowitz: Smashed beyond repair—what are you going to do with it?
Raj: What else? Sell it on ebay as "slightly used"

Penny: I was just wondering if I could talk to you. It's about Leonard.
Sheldon: Why me? Why not Koothrappali or Wolowitz?
Penny: Well, Raj can't talk to me unless he is drunk, and Wolowitz is, you know, disgusting

Leonard: Now that I'm actually about to go out with Penny, I'm not excited, I'm nauseous.
Sheldon: Then your meal choice is appropriate. Starch absorbs fluid which reduces the amount of vomit available for violent expulsion

Penny: Maybe we should talk first.
Leonard: Okay, but before you say anything, have you ever heard of Schrödinger's cat?
Penny: Actually, I've heard far too much about Schrödinger's cat.
Leonard: Good.
[Leonard kisses Penny]
Penny: Alright, the cat's alive. Let's go to dinner

The Big Bang Theory Season 1 Quotes

Penny: What actor holds the record for being named People magazine's Sexiest Man Alive?
Sheldon: William Shatner!
Leonard: I don't think it's Shatner.
Sheldon: Then it's got to be Patrick Stewart

Sheldon: I'll have a diet Coke.
Penny: Can you please order a cocktail? I need to practice mixing drinks.
Sheldon: Fine... I'll have a virgin Cuba Libre.
Penny: That's... rum and Coke without the rum.
Sheldon: Yes, and would you make it diet?