Penny: Mrs Cooper, it smells so good.
Mary Cooper: You take notes, darling. The real way to get a man is with melted cheese and cream of mushroom soup. He'll die at fifty, but his love will be true.

Mary Cooper: Oh, I so should have taken you to Houston.

Sheldon: Does this mean you're not going to sing Soft Kitty?
Mary: No, I will always sing you Soft Kitty. [sings] Soft kitty, warm kitty, little ball of fur…
Leonard: [opens door] Mrs. Cooper, were we supposed to take that pie out of the oven?
Sheldon: Get out!
Mary: Well, that was rude.
Sheldon: Well, I know, but he means well. Sing.
Mary: [sings] Happy kitty, sleepy kitty…
Sheldon: What are you trying to pull, Mom? From the top.
Mary: [to God] This is what I'm talking about. [sings] Soft kitty, warm kitty, little ball of fur…

Amy: Now Sheldon, I know you're a left handed monkey wrench but you seriously have a mortal enemy
Sheldon: Yes, in fact I have 61. Would you like to see the list?

Sheldon: [to Brent Spiner] You are now my mortal enemy.
Wil Wheaton: Don't worry it doesn't take up too much of your time.

Sheldon: You just got off the list, would you like back on it?

Bernadette: Oh, boo-hoo, you're not going to space!

Sheldon: This will just take a moment, it's on a five and a quarter inch floppy.
Amy: A floppy disk?
Sheldon: Well, I started the list when I was nine.

Sheldon: Until you either do not go or go to Wil Wheaton's party you are simultaneously my friend and not my friend. I'm characterizing this phenomenon as Schrodinger's Friendship.

Penny: Wait, what is going on?
Sheldon: In case you have forgotten, Schrodinger's cat is a thought experiment.
Penny: No, no, no, no, I didn't forget. Um, there's this cat in a box and until you open it, it's either dead or alive or both. Although, back in Nebraska, our cat got stuck in my brother's camp trunk, and we did not need to open it to know there was all kinds of dead cat in there.
Amy: Homespun stories, knowledge of physics and a bosom that defies it. You're the whole package, aren't you?

Leonard: Going to Wheaton's party is not betraying you.
Sheldon: Oh, of course you would have to believe that. Evil always thinks it's doing right. Excuse me, Stormtrooper. These are the droids you're looking for.
Leonard: I'm going to a party. I'm not turning R2-D2 and C-3PO over to the empire!
Sheldon: Not yet.

Amy: It's not for us to judge. We're just here to provide comfort and support while you come to grips with what a despicable thing you've done.

Mrs. Wolowitz: Over my dead body my son goes into outer space.

Mrs. Wolowitz: Make up all you want. Your tuchus is not leaving this planet.

Leonard: It's from Game of Thrones. What do you think?
Sheldon: I don't know. If we're going to start a fantasy sworld collection, and I've long thought we should, is this really the sword to start with?
Leonard: What did you have in mind?
Sheldon: Well, off the top of my head, I'd have to go with Excalibur. It gives you the right to rule England.
Leonard: It would be a replica of a movie prop.
Sheldon: Fair enough. It'd give you the right to rule a replica of England.