Sheldon: That was not fifteenth century soap. My God, these people need to learn you can't just put "ye olde" in front of anything and expect to get away with it.

Leonard: I've dated plenty of women. There was Joyce Kim, Leslie Winkle.
Sheldon: Notify the editors of the Oxford English Dictionary. The word plenty has been redefined to mean two.

Sheldon: Friday's always vintage game night. Look, my mom included the memory card. We can pick up where I left off in 1999 when I had pernicious anaemia.

Leonard: I would appreciate it if you would, you know, make yourself scarce.
Sheldon: Leonard, I am a published theoretical physicist with two doctorates and an IQ which can't be accurately measured by normal tests, how much scarcer could I be?

Sheldon: Of all the overrated physicists in all the labs in all the world, why does it have to be Leslie Winkle?

Penny: Sheldon, you are a smart guy, you must know-
Sheldon: Smart? I'd have to lose 60 IQ points to be classified as smart.

Sheldon: Hello to you, insufficiently intelligent person.

Leonard: You could be Batman?
Sheldon: Yeah. I'm Batman. See?

Howard: How's the air matress?
Sheldon: It's okay, if you don't mind sleeping on a bouncy castle.

Sheldon: And you thought the opposite of stupid loser was a Community College Graduate?

Sheldon: I drank milk that tasted funny.

Sheldon: When I try to deceive I have more nervous ticks than a lime disease research facility. It's a joke. It relies on a homonymic relationship between the tick the blood sucking arachnid, and tick the involuntary muscular contraction. I made it up myself.

Penny: So, do you think that if Leonard and I keep dating, Leonard would get bored with me?
Sheldon: That depends.
Penny: On what?
Sheldon: Do you have a working knowledge on Quantum Physics?
Penny: No.
Sheldon: Do you speak Klingon?
Penny: No.
Sheldon: Do you know any card tricks?

Sheldon: Why don't you just take your clothes down to the river and beat them with a rock.

Leonard: How could you just sit there and let them spy on me?
Sheldon: They were very smart. They used my complete lack of interest in what you are doing.