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

Wolowitz [to a black nurse]: Okay, I get it. I know how the world works. [flashes a five] How about I introduce you to the man who freed your people?
Nurse: Unless my people were freed by Benjamin Franklin and his five twin brothers, you are wasting your time

Sheldon: Leonard made it very clear, he doesn't want a party.
Wolowitz: Did someone say party?
Penny: He just doesn't know he wants one because he never had one.
Wolowitz: I suppose that's possible, but for the record I've never had a threesome and yet I still know I want one.
Penny: Howard here's a difference: the possibility exists that Leonard could have a birthday party before hell freezes over.
Wolowitz: Fine, if I do have a threesome you can't be part of it... I'm just kidding. Yes, you can. Can you bring a friend?

Penny: Well, Sheldon you are his friend. Friends give each other presents.
Sheldon: I accept your premise; I reject your conclusion.
Wolowitz [whispers]: Try telling him it's a non-optional social convention.
Penny: What?
Wolowitz: Just do it.
Penny: It's a non-optional social convention.
Sheldon: Ahh, fair enough.
Wolowitz: He came with a manual

Leonard: I don't celebrate my birthday.
Penny: Shut up. Yeah, you do.
Leonard: It's no big deal. It's just the way I was raised. My parents focused on celebrating achievements and being expelled from a birth canal was not considered one of them

Leonard: How did you know my birthday's Saturday?
Penny: I did your horoscope, remember? I was going to do everybody's until Sheldon went on one of his typical psychotic rants.
Sheldon: For the record, that psychotic rant was a concise summation of the research of Bertram Forer, who, in 1948, proved conclusively through meticulously designed experiments that astrology is nothing but pseudoscientific hokum.
Penny: Blah, blah, a typical Taurus

Penny [on phone]: How about this, you keep him there a little longer, and when you get to the party, I'll point out which of my friends are easy.
Wolowitz: ... Don't toy with me, woman.
Penny: I got a hot former fat girl with no self-esteem, I got a girl who punishes her father by sleeping around, and an alcoholic who's two tequila shots away from letting you wear her like a hat.
Wolowitz: Thy will be done

Raj: Missy, do you enjoy pajamas?
Missy: I guess.
Raj: We Indians invented them. You're welcome.
Wolowitz: Yeah, well, my people invented circumcision

Wolowitz: Okay, you two have to back off.
Raj: Why should I back off? You back off, dude.
Leonard: Excuse me, this is my apartment, and she's my roommate's sister.
Howard: So what? You've already got Penny.
Leonard: How do I have Penny? In what universe do I have Penny?
Wolowitz: So, I can have Penny?
Leonard: Hell, no!

I'd kill my rabbi with a pork chop to be with your sister

Wolowitz

Missy: Shelly, can I speak to you a minute—alone?
Sheldon: Why does everyone suddenly want to talk to me alone? Usually no one wants to be alone with me

Sheldon: You see, I'm a superior genetic mutation, an improvement on the existing mediocre stock.
Missy: And what do you mean, "mediocre stock?"
Sheldon: That would be you

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: Here's the problem with teleportation.
Leonard: Lay it on me.
Sheldon: Assuming a device could be invented, which would identify the quantum state of matter of an individual in one location and transmit that pattern to a distant location for reassembly. You would not have actually transported the individual, you would have destroyed him in one location and recreated him in another.
Leonard: How about that.
Sheldon: Personally, I would never use a transporter because the original Sheldon would have to be dissintegrated in order to create a new Sheldon.
Leonard: Would the new Sheldon be in any way an improvement on the old Sheldon?
Sheldon: No, he would be exactly the same.
Leonard: That is a problem