At least my mother made her boyfriend climb out the window.

Howard: Attention people of Earth: Tonight, there will be two moons in the sky.

They left dogs up here in the 60s.

Howard's mother: Speak up!
Howard: From now on she's the only woman who can yell at me!

Howard: There's fuel leaking and we're still gonna go?
Cosmonaut: Don't lose your Fruit Loops, Fruit Loops.

Sheldon: He asked her during coitus.
Howard: Did he get down on one knee or were you already there?

No! When I eat Fruit Loops the other astronauts make fun of me.

Quick question. I missed it in the briefing. How much urine do these suits hold?

Bernadette's father: You go up to that space station and you make me proud.
Howard: Um, okay.
Bernadette's father: You got a problem with that?
Howard: All right, look, I'm going to level with you. I'm terrified about going into space. What if I don't make it back?
Bernadette's father: It's gonna be okay, son.
Howard: You really think so?
Bernadette's father: Of course. A pretty girl like Bernadette ... she'll find a new guy.

Howard: Let me explain the difference between you and me. You watch 'Star Trek'; I live it.
Raj: Oh, please, I don't remember the episode of 'Star Trek' where the guy never goes to space and brags about it in a tuxedo store.
Howard: Make all the jokes you want. There is only one of us here brave enough to almost do what I almost did.

Yes! Thank you! Oh! Oh ... I'm not gonna die in space! I'm gonna die the way God intended in my late 50s with a heart full of pastrami.

Howard: Tell her I'm really sorry. And if she doesn't want to marry me, I get it. But what I really want her to know is the guy that she is really disgusted by is the guy that I'm disgusted by, too. But, that guy doesn't exist anymore; he's gone. And the reason is because of her. So, if this relationship is over, let her know that she made me a better man, and tell her thank you.
Penny: Oh my god, Howard! That's the most beautiful thing I've ever heard. And it came out of you.

TBBT Quotes

Sheldon: Are you still mad about the sperm bank?
Leonard: No!
Sheldon: Do you want to hear an interesting thing about stairs?
Leonard: Not really.
Sheldon: If the height of a single step is off by as little as two millimeters most people will trip.
Leonard: I don't care—two millimeters?! That doesn't seem right.
Sheldon: No, it's true! I did a series of experiments when I was twelve; my father broke his clavicle.

Penny, there's only one cookie with something in the middle that solves life's problems, and that's an Oreo. Or a Nutter Butter, if you're in a pinch.

Sheldon