Sheldon: Okay. Scratch paper, check. Whiteboard, check. Chex Mix, check. And here we go.

Mary Cooper: Hello again.
Sheldon: Who did you see at the barbecue festival?
Mary Cooper: Mr. Watkins.
Sheldon: Really? You called me and interrupted my work to tell me that you ran into somebody you could plausibly run into? I'm sorry, Mother, I really need to focus here. I will speak to you next week.
Mary Cooper: Okay, sweetheart. I'll talk to you then.

Sheldon: (sighs) I thought Mr. Watkins moved to Florida.
Mary Cooper: He did. He was back visiting his son.
Sheldon: Oh, gosh darn it, that is interesting. Was it Tommy or Joe? I bet it was Joe, 'cause he and Tommy had a falling out over that time-share.

Sheldon: Did I actually do it? I did. I did. [picks up his phone and dials] The answer is one in 18 million.
Mary Cooper: What is?
Sheldon: The odds of you running into Mr. Watkins.

Penny: [3 knocks] Sheldon? [3 knocks] Sheldon? [3 knocks] Sheldon?
Sheldon: It's annoying when you do it.

Sheldon: I have been working pretty hard. I could use a break.
Penny: What's that?
Sheldon: Oh, yeah, that is an experiment to see how many parallelograms I could draw while holding my breath.
Penny: [pointing to the board] Is that where you blacked out?
Sheldon: [pointing behind the couch] No, actually, that's where I blacked out.

Penny: And this?
Sheldon: That is a list of all the different types of natural disasters.
Penny: "Fire-quake"?
Sheldon: I made that one up. Which I shouldn't have, because now I'm scared of it.

Penny: Maybe I'll just eat this in the laundry room.
Sheldon: No, no. Wait. You don't have to go, as long as you sit quietly and don't say anything.

Sheldon: Thank you for driving me to work.
Penny: You know this is my day off, Sheldon.
Sheldon: Oh, good. I'm not keeping you from anything.

Sheldon: You're going up Euclid Avenue?
Penny: Mm-hmm.
Sheldon: Leonard takes Los Robles Avenue.
Penny: Well, good for Leonard.
Sheldon: Euclid Avenue is shorter as the crow flies, but it has speed bumps, which appreciably increase point-to-point drive time, making it the less efficient choice. But you have the conn. Of course, if you're not going to slow down for the speed bumps, I withdraw my previous objection.

Sheldon: Okay. I'll say an element, and uh, you say an element whose name starts with the last letter of the one I said, okay? I'll start. Helium. Now, you could say Mercury. That would give me a Y. Ooh, very clever, that's a tough one. So I go Ytterbium, which gets you back to M. So you go Molybdenum, and I say Magnesium, you say Manganese, and I say Europium, and, and you're left with Mendelevium, and there are no more M's because I believe that Meitnerium should still be called Ekairidium, so congratulations, you win. Do you wanna go again?

Sheldon: Oh, Leonard, there you are, I'm ready to go home.
Leonard: I just got here.
Sheldon: Good, perfect timing.

Sheldon: Where are you going?
Raj: I'm taking you home.
Sheldon: Oh, but I'm not going home. It's Wednesday. Wednesday is new comic book day. We have to go to the comic book store. And then we have to stop at Soup Plantation, it's creamy tomato soup day, and Radio Shack, there's a sale on triple-a batteries. Plus, we have to go to Pottery Barn and return my Star Wars sheets.
Raj: I have a better idea.
Sheldon: You want to go to Pottery Barn first?

Leonard: Sheldon, sit down.
Sheldon: She's in my spot. Don't look at me like that. Everybody knows that's my spot.

Howard: Sheldon, why are you arguing with the DMV?
Sheldon: How else are they going to learn? Look, question 2, "When are roadways most slippery?" Now, okay, there are three answers, none of which are correct. The correct answer is, when covered by a film of liquid sufficient to reduce the coefficient of static friction between the tire and the road to essentially zero, but not so deep as to introduce a new source of friction.