Howard: Hope you don't mind, I told my girlfriend, Bernadette, she can join us for dinner.
Leonard: Sure, the more the merrier.
Sheldon: Wait, no. That's a false equivalency. More does not equal merry. If there was 2000 people in this apartment right now, would we be celebrating? No, we'd be suffocating.

Leonard: I think I'm starting to get this.
Rajesh: Really? The only thing I've learnt in the last 2 hours is that American men drink a lot of beer, pee too often and have trouble getting erections.
Leonard: Focus on the game, not the commercials Raj.

Girl: What are you gonna get, Raj?
Raj: With my luck, hepatitis.

Sheldon: Where's the ring?
Leonard: It's in a Fedex box on its way back to where it came from.
Raj: The fires of Mount Doom?

Sheldon: I am the ball, my thoughts are its thoughts, its holes are my holes.

Leonard: When we watch Frosty the Snowman, he roots for the sun.
Sheldon: Excuse me, but the sun is essential for all life on earth. Frosty is merely a bit of frozen, supernatural ephemera in a stolen hat. A crime, by the way, for which he is never brought to account.

Wolowitz: Well no, you're mistaken. You give speeches all the time. What you can't do is shut up.

Howard: Sheldon knows football? I mean Quidditch, sure, but football?

Sheldon: You can't make a half sandwich. If it's not half of a whole sandwich, it's just a small sandwich.

Sheldon: What are they doing here?
Leonard: We came to apologize again and bring you home. So why don't you pack up your stuff, and we'll head back?
Sheldon: No, this is my home now. Thanks to you, my career is over, and I will spend the rest of my life here in Texas trying to teach evolution to creationists.
Mrs. Cooper: You watch your mouth, Shelly. Everyone's entitled to their opinion.
Sheldon: But evolution is not opinion, it's a fact.
Sheldon's mom: And that is your opinion.

Penny: Don't you dare knock!

Howard: I have a two-part question.
Sheldon: Go ahead.
Howard: A: Are you kidding? And B: Seriously, are you freaking kidding me?
Sheldon: A: I rarely kid, and B: when I do kid, you will know it by my use of the word "Bazinga".
Howard: So you're saying the two of you are going to be sleeping in the same bed?
Sheldon: Yes. Bazinga.

Leonard: Okay, I know what you're doing.
Sheldon: Really?
Leonard: Yes, you're using chocolates as positive reinforcement for what you consider correct behavior.
Sheldon: Very good. Chocolate?
Leonard: No, I don't want any chocolate! Sheldon, you can't train my girlfriend like a lab rat.
Sheldon: Actually, it turns out I can.

Barry Kripke: Hey, Cooper. I hear you're going to be on the radio with Ira Flatow from Science Friday next week.
Sheldon: Thank you, Kripke, for depriving me of the opportunity to share my news with my friends.
Barry Kripke: My pleasure.
Sheldon: My thanks were not sincere.
Barry Kripke: Ah, but my pleasure is.

Sheldon: Leonard, when that woman moved in three years ago I told you not to talk to her, and now look. We're going to be late for the movies.