Leonard: See, the liquid metal Terminators were created in the future by Skynet, and Skynet was developed by Miles Dyson, but that future no longer exists due to Dyson's death in Terminator 2.
Sheldon: Okay, then riddle me this. Assuming all the good Terminators were originally evil Terminators created by Skynet but then reprogrammed by the future John Connor, why would Skynet, an artificial computer intelligence, bother to create a petite hot 17 year-old killer robot?
Leonard: Skynet is kinky? I don't know.
Sheldon: Artificial intelligences do not have teen fetishes.

Leonard: Do you have a cousin Leopold?
Sheldon: No, I made him up. I think you'd call him Lee.
Leonard: I don't get it. I already told her a lie. Why replace it with a different lie?
Sheldon: Well, first of all, your lie was laughably transparent, where mine is exquisitely convoluted. While you were sleeping I was weaving an un-unravelable web.
Leonard: un-unravelable?
Sheldon: Yes, if she Googles "Leopold Houston" she'll find a Facebook page, an online blog depicting his descent into drug use, and a desperate yet hopeful listing on e-Harmony.com.

Sheldon: Leonard? Leonard?
Leonard: What?
Sheldon: You realize you and I could become brothers.
Leonard: We're not gonna be brothers. We're not gonna be step brothers. Go to sleep.
Sheldon: I hope you're right. 'Cause a grown man living with his brother and his brother's wife is weird.

Sheldon: Everything is stupid and I want to go home.
Leonard: That's Sheldon's way of saying he's proud of Bert, too.

Amy: What's wrong?
Sheldon: I'm not sure. Earlier tonight, things began organically, and now it's feeling forced, like all the Pirates of the Caribbean sequels.

Sheldon: Of course you're fine. Not every member of a species finds a mate. Sir Isaac Newton died a virgin. Look at the contributions he made.
Raj: I'm not a virgin, Sheldon.
Sheldon: Wha- So now you think you're better than Isaac Newton?

Raj: It's nice to see you taking an interest in Amy's work.
Sheldon: Well, don't get me wrong. Neurobiology's nothing more than the science of gray squishy stuff. But, you know, when it connects to physics, gas up the Ford, Martha, we're going for a drive.

Sheldon: What? You hold my hand, you kiss my mouth, but you draw the line at 102 fever? What happened to our love?

Sheldon: You know, also, if they did have coitus, we'll all be needing a skilled psychiatrist.

Alfred Hofstadter: You're a patient young lady.
Sheldon: Hey, hey! She's mine! Take a cold shower, grandpa!

Howard: I'm not even sure that's possible.
Colonel Williams: Well, I ran it by some colleagues at MIT, and they thought they could get it done in four months.
Howard: Four months?
Sheldon: Yeah, we'll do it in two! (laughs) Hi, I'm Dr. Sheldon Cooper. I'm the actual brains behind this project. Also, engineers aren't real scientists, MIT's a trade school, and the Death Star is from Star Wars, not Star Trek! But otherwise, thank you for your service.

Leonard: Wish we weren't so far from my parking space.
Sheldon: The way you put away those lemon bars, perhaps that's a good thing.
Leonard: I'd like to reinstate the you-not-talking rule.
Sheldon: Why? It clearly doesn't work.

Amy: Sheldon, I've made more than enough accommodations for you. We're both grown adults. We've been far more intimate than this. If you don't want to snuggle, fine. But we're not building a pillow wall.
Sheldon: Okay, well, I am sorry. I'm just worried that my sensitivity to temperature could make this a rough night. And no offense, but your bottom radiates enough heat, I'm surprised there aren't iguanas lying on it.

Sheldon: Buda and Pest united to form Budapest. And that's why Budapest is the "Budabest".

Sheldon: Hey, it's not even called the "Genius Grant," it's the MacArthur Fellowship. Just like it's not Frankenstein, it's "Frankenstein's Monster." Which brings us back to that hulking simpleton over there. And if anyone's a genius, it's me for the way I brought that full circle.