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

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

Sheldon: I can't believe he fired me.
Leonard: Well, you did call him a "glorified high school science teacher whose last successful experiment was lighting his own farts."
Sheldon: In my defense, I prefaced that with, "with all due respect."

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

Sheldon: I have got the Sword of Azeroth!
Leonard: Forget the sword, Sheldon. Help Raj.
Sheldon: There is no more Sheldon. I am the sword master!
Wolowitz: Leonard, look out!
Leonard: Damn it, Sheldon, we're dying here.
Sheldon: Goodbye, peasants.
Leonard: Bastard teleported!
Raj: He's selling the Sword of Azeroth on eBay.
Leonard: You betrayed us for money? Who are you?
Sheldon: I'm a rogue night elf. Don't you people read character descriptions? Wait, wait, wait... somebody just clicked Buy It Now.
Wolowitz: I am the sword master!

Wolowitz: So, how'd it go with Leslie?
Leonard: Oh, we tried kissing, but the earth didn't move... I mean any more than the 383 miles it was gonna move anyway

Leonard: No, I'm done with Penny. I'm going to be more realistic and go after someone my own speed.
Raj: Like who?
Leonard: I don't know... Olivia Geiger?
Sheldon: The dietitian at the cafeteria with the limp and lazy eye?
Leonard: Yes.
Sheldon: Well, I don't think you have a shot there

Sheldon: I have noted that Leslie Winkle recently started shaving her legs. Now, given that winter is coming, one can only assume that she's signaling sexual availability.
Wolowitz: I don't know. You guys work in the same lab.
Leonard: So?
Wolowitz: There are pitfalls. Trust me, I know. When it comes to sexual harassment law, I'm a bit of a self-taught expert.
Leonard: Look Howard, if I were to ask Leslie Winkle out, it would just be for dinner. I'm not going to walk into the lab, ask her to strip naked and dance for me.
Wolowitz: Oh, then you're probably okay

[trying to assemble Penny's new wardrobe, reading the instructions]
Wolowitz: Oh, boy! I was afraid of that!
Leonard: What?
Wolowitz: These instructions are a pictographic representation of the least imaginative way to assemble these components. This, right here, is why Sweden has no space program

Sheldon: I couldn't sleep knowing that just outside my bedroom is our living room and just outside our living room is that hallway and immediately adjacent to that hallway is this! (showing Penny's messed up apartment)
Leonard: Do you realize if Penny wakes up there's no reasonable explanation to why we are here?
Sheldon: I just gave you a reasonable explanation.
Leonard: No, no. You gave me an explanation. Its reasonableness will be determined by a jury of your peers

Sheldon: You do understand that our efforts here will in no way increase the odds of you having sexual congress with this woman?
Leonard: Men do things for woman without expecting sex.
Sheldon: Those would be men who just had sex

Leonard: I guess we'll just bring it up ourselves.
Sheldon: I hardly think so.
Leonard: Why not?
Sheldon: Well, we don't have a dolly, or lifting belts, or any measurable upper-body strength.
Leonard: We don't need strength. We're physicists. We are the intellectual descendants of Archimedes. Give me a fulcrum and a lever, and I can move the Earth. (Trying to move the box) It's just a matter of... I don't have this. I don't have this. I don't have...
Sheldon: Archimedes would be so proud

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?