Leonard: Thought you were getting us dinner.
Penny: Sorry. I had to stop at Sheldon's and help him solve string theory.
Amy: What?
Penny: Yeah, turns out the answer's knots.
Leonard: That's cute, but you can't have knots in more than four dimensions.
Penny: Mmm ... you can if you consider them sheets. [chuckling] Good night.

Amy: Maybe we should just get married at City Hall and forget about everything else.
Sheldon: City Hall, hmm. I do like metal detectors and the sound of permits being denied.

Howard: Why would the military want Sheldon?
Leonard: I don't know. Target practice?

Sheldon: You know what they say, fool me "N" times, where "N" equals the amount of times you've already fooled me, shame on you. Fool me "N" plus one times, shame on me.

Sheldon: Neither of them will be the actual cake. I'm just using it as a bargaining chip to get Amy to agree to the whole wedding party getting rings and us getting one ring to rule them all.
Howard: I forget, which mental hospital are you guys registered at?

Mary Cooper: Oh, Shelly. I have bad news. Mr. Watkins passed this morning.
Sheldon: Oh. Oh, I'm-I'm sorry.
Mary Cooper: I know. What are the odds of that?
Sheldon: Call you back.

Sheldon: Are you having an allergic reaction to my boutonniere?
Leonard: No. I'm just so happy for you. And for me. After today, you are officially - and, more important, legally - Amy's problem.
Sheldon: Don't be silly, Leonard. I will always be your problem.

Sheldon: Amy, I usually know exactly what to say. But in this moment I have no words.
I guess I'm overwhelmed by you. In a good way. Not in the elevator in the Haunted Mansion way. Even if I can't tell you now how I feel, I will spend my life showing you how much I love you.

Bernadette: At the office, I have two assistants! I don't even know their names. I just call them Thing 1 and Thing 2.
Amy: I don't have assistants.
Bernadette: I guess that's one of the benefits of being in the private sector. That and all the money I make!

Sheldon: Sorry, but when you make a discovery like this, you don't just take it down to City Hall. You tell the whole world. And so I'll say it in Latin or Klingon or smoke signals, if that's not cultural appropriation.
Amy: It is.
Sheldon: Okay, so not smoke signals.

Leonard: Hey, what's going on with your hair?
Raj: Uh, nothing. I just decided to stop straightening it.
Penny: Wait, so you were making your hair look like that on purpose?
Raj: When I first moved to America, I wanted to fit in. And Howard's hair was straight, and he was the coolest person I knew.
Penny: Then you never saw any other people?

Amy: I can't believe we're doing this.
Sheldon: I know. I'm getting married. The new Star Wars movie's coming out. We are really finishing this year strong.
Amy: Okay, but of the two of tho- You know, I'm not even gonna ask. I'm not gonna ask.

Penny: I'm not leaving you for Bill Gates.
Leonard: You sure? I bet his Internet's really fast.

Leonard: Come on. You can build things. You were an astronaut.
Howard: That's true. You know, as a kid, I used to make model rockets. That'd be pretty cool to do with a son.
Sheldon: Model rockets. Finally, something interesting! What is your preferred mode of recovery?
Amy: Sheldon, we're helping our friends.
Sheldon: And we got to model rockets, yeah? It was a tedious road, but well worth the effort.
Amy: So, have you thought of any names?
Sheldon: Amy, we finally got to model rockets. Why are you turning back?

Penny: Leonard thinks when we broke up, it didn't bother me.
Zack: That's crazy. When we were going out, she used to talk about you all the time. In fact, I think she only dated me because I reminded her of you.
Leonard: Sure. Because we're both people?
Zack: Damn right we are.