Howard: It's pretty late. You think I've got time to run some more simulations on the cooling system?
Leonard: Sure, I'm still figuring out the thermo-acoustic expander.
Sheldon: Oh, while you do that I am going to pump cerebral spinal fluid through my brain cells to remove the metabolic by-products of the day's thoughts.
Howard: What?
Sheldon: It's called sleep and it's my bedtime. Nighty-night, y'all.

Penny: We wouldn't even sit in your spot while you're gone.
Sheldon: You're darn right, you wouldn't. No matter where I am, this will always be my spot. Like an embassy in a foreign country, this seat is the sovereign soil of my bottom.

Sheldon: Oh, good Lord! Is that mistletoe? Don't you maniacs own a calendar?

Leonard: Sheldon, I know what you did, now change the password back.
Sheldon: Well, powder me in sugar and call me a donut, if it isn't Leonard Hofstadter.

Penny: Now Sheldon's popular? What is happening?!

Sheldon: It's not my fault I'm bad at sharing; I skipped kindergarten.

Bernadette: Sorry I flipped out on you. I think it's just hormones.
Raj: I think you were mean before you were pregnant, but it's fine.

Raj: Does this place look familiar?
Sheldon: It's hard to say.
Bartender: Hey, Sheldon's back!
Everybody: Sheldon!
Sheldon: It's getting clearer.

Bernadette: Do you know what? It's just a research project. The most important job in the world is gonna be raising this child. It's all I need to give my life meaning.
Penny: Oh, that's so beautiful.
Bernadette: You believe me? Oh, good. Eleven more chumps like you, I'll have the jury eating out of my hand.

Howard: Well, why would you do that?
Colonel Williams: You guys completed phase one, we'll take it from here.
Sheldon: Where did you move it?
Colonel Williams: I can't tell you that.
Leonard: Are you implementing phase two?
Colonel Williams: I can't tell you that.
Sheldon: Wait, so you're just going to take all the work we've done for the last year and toss us aside?
Colonel Williams: That one I can tell you, yes.
Howard: This is all very upsetting.
Colonel Williams: I'm sorry to hear that. As you know, the primary focus of the United States military is people's feelings.
Sheldon: If that's sarcasm, please save it for our enemies.

Beverly Hofstadter: I don't see why I should have to watch your father parade around with some Bible-thumping bumpkin.
Sheldon: Oh. Excuse me, that is my mother you're talking about, however accurately.

Sheldon: *knock knock knock* Amy. *knock knock knock* Amy. *knock knock knock* Amy.
[Amy opens the door. Sheldon is on one knee, holding out an engagement ring]
Sheldon: Will you marry me?

Howard: How'd you even get that up the stairs?
Sheldon: I said to myself, "I think I can, I think I can." And then I couldn't, so I paid two men who promised not to come rob us later.

Sheldon: I don't understand why I can't talk at this meeting.
Leonard: 'Cause when you talk, it enrages people.

Raj: I'm sorry, guys. Sheldon was upset, Leonard and Penny were fighting. I just wanted to go someplace where I wasn't causing problems.
Howard: (sighs) I'll say it again. India.