Wolowitz [about Sheldon]: How long's he been stuck?
Leonard: Intellectually about 30 hours, emotionally about 29 years.
Wolowitz: Have you tried rebooting him?
Leonard: No, I think it's a firmware problem.

Wolowitz: I once dated a girl who believed she was abducted by aliens.
Leonard: And that didn't bother you?
Wolowitz: Au contraire; it meant she was gullible and open to a little probing.

Sheldon: How was your date?
Leonard: Awesome!
Sheldon: Score one for liquor and poor judgment

Leonard: How can you have a girlfriend you can't even speak to women?
Raj: Two words: deaf chick. It doesn't matter if i can't talk cause she can't hear me.
Leonard: What?
Raj: That's what she said.

Leonard: I'm her friend, I'm not going to take advantage of her vulnerability.
Wolowitz: Wait, so you're saying that if in the depths of despair she throws herself at you and demands you take her right there, right now, you'll just walk away?
Leonard: I said I'm her friend, not her gay friend

Leonard: You're my woman. I'm going to make you feel things you have never felt before.
Priya: Leonard
Leonard: That's right, say my name and beg me for more because I'm going to give it to you.
Priya: My parents are here.
Priya's father: Hello, Leonard, if I may also say your name.

I'm still not adjusted to how SyFy spells their name now. S-Y-F-Y... that's siffy.

Leonard: Oh, geez, I - I don't know if I can ditch Priya two nights in a row.
Raj: Oh, come on, man. Bros before... my sister.

Sheldon: Are you upset about something?
Leonard: What was your first clue?
Sheldon: Well, it was a number of things: first, the late hour; then your demeanor seems very low energy; plus your irritability...
Leonard: Yes, I'm upset!
Sheldon: Huh, I don't usually pick up on those things. Good for me.
Leonard: Yeah, good for you.
Sheldon: Oh, wait, did you want to talk about it?
Leonard: I don't know, maybe.
Sheldon: Wow, I'm on fire tonight

[at the high-IQ sperm bank discussing donating...]
Sheldon: What if she ends up with a toddler who doesn't know if he should use an integral or a differential to solve for the area under a curve?
Leonard: I'm sure she'll still love him.
Sheldon: I wouldn't

Sheldon: Looking out at your fresh young faces, I remember when I, too, was deciding my academic future as a lowly graduate student. Of course, I was fourteen. And I had already achieved more than most of you could ever hope to, despite my 9:00 bedtime. Now, there may be one or two of you in this room who has what it takes to succeed in theoretical physics, although it's more likely that you'll spend your scientific careers teaching fifth graders how to make papier-mâché volcanoes with baking soda lava.
Leonard: Oh, good God.
Sheldon: In short, anyone who told you that you would someday be able to make some significant contribution to physics, played a cruel trick on you—a cruel trick indeed. Any questions? ... Of course not. I weep for the future of science

Leonard: Beekeeper to King 12. I capture your pope and release the swarm. Checkmate on Sheldon.
Sheldon: I knew I should've given my pope the jet pack.

TBBT Quotes

Oh, Bernadette, please play my clarinet.

Raj's poem

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?