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

I think that you have as much of a chance of having a sexual relationship with Penny as the Hubble telescope does of discovering at the center of every black hole is a little man with a flashlight searching for a circuit breaker.

Sheldon

There's always a chance that alcohol and poor judgment on her part may lead to a wonderful evening

Sheldon

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

Leonard: If you don't have any other plans, do you want to join us for Thai food and a Superman movie marathon?
Penny: A marathon? Wow, how many Superman movies are there?
Sheldon: You're kidding, right?

Excuse me, explain to me an organizational system where a tray of flatware on a couch is valid? Now, I'm just inferring that this is a couch, because the evidence suggests that the coffee table is having a tiny garage sale

Sheldon

Penny: So, what do you guys do around here?
Sheldon: Well, today we tried masturbating for money

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?