Sheldon: Excuse me. This is not about protecting my friend. Im a big fan of homeostasis. Do you know what that is?
Penny: Of course not.
Sheldon: Homeostasis refers to a systems ability to regulate its internal environment and maintain a constant condition of properties like temperature or pH.
Penny: Worst bedtime story ever!

Penny: Ooh, one gravy boat.
Amy: That's from Sheldon. He told me he had it engraved.
Bernadette: In the event of divorce, please return to Sheldon Cooper.
Penny: One inappropriate, yet I wish I thought of that, gravy boat.

Penny: So, does Sheldon have anything special planned for you tomorrow night?
Amy: Oh, yes. According to the relationship agreement, on the anniversary of our first date, he must take me to a nice dinner, ask about my day, and engage in casual physical contact that a disinterested onlooker might mistake for intimacy.
Penny: That's hot. You kids better use protection.

Penny: Gosh, I worked my ass off today. This is exactly what I needed.
Leonard: Great. Just relax and enjoy. Tonight is all about you.
Penny: Aw, thank you.
Leonard: So, where exactly are we in this relationship?
Penny: Oh, come on.

Penny: Hey, I know tons of people who got married in Vegas.
Bernadette: Are any of them still married?
Penny: Yeah. I mean not to the same people, but...

Penny: I can't believe it. This whole time, a small part of me thought he was lying.

Leonard: I'm sorry. I- I crossed a line. I didn't mean to!
Penny: Who says something like that right in the middle of sex?
Leonard: I don't know, it just came out. People say weird things during sex all the time.
Penny: Okay, well, they sure as hell don't say that.
Leonard: It was the heat of the moment.
Penny: No, the heat of the moment is, ooh, yeah, just like that, not will you marry me?
Leonard: I'm sorry. Just, just give me another chance.
Penny: Why, so you can crawl under the covers and go, hey, baby, want to go look for houses in neighborhoods with good schools?

Leonard: It's a bachelor party. There could be strippes. Wouldn't that make you jealous?
Penny: Come on, Leonard, it's you. What's going to happen? I mean, even if there is a stripper, all you'd do is avoid eye contact and maybe offer to help her kid with homework.

Penny: Well, have fun tonight.
Leonard: Oh, I will. There is no telling what might happen.
Penny: Yes, there is.

Bernadette: I've actually been thinking I'm going to hyphenate, Bernadette Mary-Ann Rostenkowski-Wolowitz.
Penny: Nice. You know, you should totally get BernadetteMaryAnnRostenkowskiWolowitz.com before someone snaps it up.
Bernadette: Howard already took care of it.

Bernadette: When I first met Howard, he seemed so innocent to me, just a sweet little guy who lives with his mother.
Penny: Well, if that's what you like, I'll take you to the comic book store, the place is full of 'em.
Bernadette: Wait a minute. You set me up with Howard. Did you know about all the creepy stuff he was into?
Penny: Well, a little. You hear stuff.

Bernadette: Why didn't you tell me?
Penny: Well, I was gonna, but I didn't think it would go past the first date. Then, when it did, I thought for sure it wouldn't go past you meeting his mother. Definitely not past the two of you sleeping together. I mean, the warning signs were there, this is really on you.

Penny: Oh, my God, Howard. That's the most beautiful thing I've ever heard. And it came out of you.

Penny: Hey.
Sheldon: Hello.
Penny: It's not Saturday night. Why are you doing your laundry?
Sheldon: This is not my laundry.
Penny: Wow, are these Amy's? Kind of trashy, good for her.
Sheldon: Those are Howard's.
Penny: Ugh.

Penny: Why are you washing Howard's man panties?
Sheldon: Because if I don't, he won't give my paper to Stephen Hawking. He's a famous physicist.
Penny: Yeah, yeah, I know. He's the wheelchair dude who invented time.
Sheldon: That's close enough.