Penny: Leonard, you're back.
Leonard: Yeah, I just stopped by to say… [Penny grabs Leonard and kisses him] Yeah, so, hi!
Penny: Hi! [They stumble into her apartment while kissing]

Leonard: So, how'd you two guys meet?
Zack: My company designs the menus for the Cheesecake Factory.
Leonard: Your company?
Zack: Well, it's my dad's, but me and my sister are VPs.
Leonard: So, menus?
Zack: I know it sounds easy but there's a lot of science that goes in designing them.

Amy: You should also know that all physical contact, up to and including coitus, is off the table.
Sheldon: May I buy you a beverage?
Amy: Tepid water please.
Wolowitz: My God, what have we done?

Zack: Hey, I want to see this laser thing.
Penny: Oh, but what about the party?
Zack: It's a surprise party, doesn't matter when we get there.

Leonard: Don't worry about the moon. We, we set our laser to stun.
Zack: Smart.
Leonard: Now, we'll be able to see the beam when it leaves, but it won't be strong enough when it comes back to be seen by the naked eye.
Zack: (chuckling) Naked.

Penny: When I was a senior in high school, one of my friends heard I was gonna be named head cheerleader, I was so excited. My mom even made me a celebration pie. Then they named stupid Valerie Mossbacher head cheerleader, big old slutbag.
Sheldon: Are you saying that you think a celebration pie is even remotely comparable to a Nobel Prize?
Penny: Well, they're pretty tasty.
Sheldon: And on a different, but not unrelated topic, based on your current efforts to buoy my spirits, do you ever truly believe that you were fit to be a cheer leader?

Leonard: Two degrees, Sheldon. I just want to turn the thermostat two degrees.

Penny: Ah, it's nice having the place to ourselves, isn't it?
Leonard: Uh-huh. Now that Raj is working for Sheldon, I don't have to chauffeur him around anymore. Plus, yeah, with them working late so much, we get some privacy.
Penny: Mm-hmm. Hey, want to get a little crazy?
Leonard: What are you thinking?
Penny: Let's slide over to Sheldon's spot and make out.
Leonard: You are a dirty girl.

Leonard: Dr. Cooper?
Louis: No, you want the crazy guy next door.

Leonard: There you go, three against one.
Sheldon: They don't get a vote. It's one against one. And according to the roommate agreement, all ties will be settled by me.
Leonard: But I said no to that.
Sheldon: And I said yes. And I settle all ties.

Leonard: Not only did Sheldon save my life, he didn't rat me out to the landlord. Or the police. Or Homeland Security.
Penny: Okay, so, basically, you're the reason I have to walk up and down three flights of stairs every day?

Sheldon: Roommates agree that Friday nights shall be reserved for watching Joss Whedon's brilliant new series Firefly.
Leonard: Does that really need to be in the agreement?
Sheldon: We might as well settle it now, it's going to be on for years.

Sheldon: That's correct. FYI, I would have accepted any answer other than procreating. Come, I'll show you the rest of the apartment.
Leonard: Oh, good. I passed the barriers.
Sheldon: The second barrier. Don't get cocky.

Sheldon: Third barrier passed. You have won the right to see your room. Huzzah!
Leonard: Is this it?
Sheldon: No, this is my room. People don't go in my room.
Leonard: So where do you sleep?
Sheldon: I don't understand.
Leonard: If people don't go in there, and you're people, and… You are people, aren't you? Making a joke.
Sheldon: Do you do this often?
Leonard: On occasion.

Sheldon: And next, if either of us ever invents time travel, we agree our first stop will be this meeting today in precisely five seconds.
Leonard: Okay. [They look around, nothing happens]
Sheldon: Well that's disappointing.