Leonard: So, what happens now?
Leslie: Well, I don't know about your sex drive, but I'm probably good till New Year's.
Leonard: Oh. Okay. Thank you.
Leslie: Thank you.
Leonard: You want to make plans for New Year's?
Leslie: Whoa, Leonard, please. You're smothering me

Penny: Leonard, I didn't know you played the cello.
Leonard: Yeah, my parents felt that naming me Leonard and putting me in advanced placement classes wasn't getting me beaten up enough

Sheldon: Who told you you could touch my board?
Leslie: No one.
Sheldon: I don't come in to your house and touch your board.
Leslie: There are no incorrect equations on my board.
Sheldon: Oh! That is so, so...
Leslie: I'm sorry; I've got to run, if you come up with an adjective text me.
Sheldon: Inconsiderate, that is the adjective, inconsiderate!

Leslie: I'm glad I ran into you. The Physics Department string quartet needs a new cellist.
Leonard: What happened to Elliot Wong?
Leslie: He switched over to high-energy radiation research and had a little mishap, and now the other guys are a little uncomfortable sitting next to him

Leslie: Listen, neither of us are neuroscientists, but we both understand the biochemistry of sex. I mean, dopamine in our brains is released across synapses, causing pleasure. You stick electrodes in a rat's brain, give him an orgasm button, he'll push that thing until he starves to death.
Leonard: Well, who wouldn't?
Leslie: Well, the only difference between us and the rat is that you can't stick an electrode in our hypothalamus. That's where you come in

I saw your pupils dilate when you looked at her, which, unless you're a heroin addict, points to sexual attraction

Leslie [about Leonard's interest in Penny]

Leslie: Just so we're clear, you understand that me hanging back to practice with you is a pretext for letting you know that I'm sexually available.
Leonard: Really?
Leslie: Yeah. I'm good to go.
Leonard: I thought you weren't interested in me.
Leslie: That was before I saw you handling that beautiful piece of wood between your legs

Penny: What's the matter?
Sheldon [confused by Leonard having Leslie in his room]: I don't know what the protocol is here. Do I stay? Do I leave? Do I wait to greet them with a refreshing beverage?
Penny: Gee, Sheldon, you're asking the wrong girl. I'm usually on the other side of the tie.

Sheldon: Can't we just go to Big Boy? They only have one burger: the Big Boy.
Penny: The Barbecue Burger is like the Big Boy.
Sheldon: Excuse me, in a world that already includes a Big Boy, why would I settle for something that's like a Big Boy?

Sheldon: I need your help in a matter of semiotics.
Penny: What?
Sheldon: Semiotics, the study of signs and symbols as a branch of the philosophy related to linguistics.
Penny: Okay, honey, I know you think you are explaining yourself, but you're really not

The Big Bang Theory Season 1 Episode 5 Quotes

Sheldon: Can't we just go to Big Boy? They only have one burger: the Big Boy.
Penny: The Barbecue Burger is like the Big Boy.
Sheldon: Excuse me, in a world that already includes a Big Boy, why would I settle for something that's like a Big Boy?

Sheldon: I need your help in a matter of semiotics.
Penny: What?
Sheldon: Semiotics, the study of signs and symbols as a branch of the philosophy related to linguistics.
Penny: Okay, honey, I know you think you are explaining yourself, but you're really not