Sheldon: There's a lot of harm in trying something new. That's why we test out drugs and cosmetics on bunny rabbits.

Sheldon: # Nobody knows the trouble I've seen. Nobody knows my sorrow. #

Sheldon: How would one measure a sense of humor? A humormometer?

Penny: I found the decaf.
Stuart: Oh, great.
Sheldon: Herbal tea for me, please.

Penny: How is that not talking to me like I'm an idiot? It's my friend, it's my couch, and it's my freakin' life!
Sheldon: It's also your roll.

Howard: What's this? (hand movement)
Sheldon:That's what you did. I assumed, as in a number of languages, that the gesture was part of the phrase.
Howard: Well, it's not.
Sheldon: Why am I supposed to know that? As the teacher, it's your obligation to separate your personal idiosyncrasies from the subject matter.

Sheldon: I may be an alien, but I have urges. If Amy wants to copulate by firing her eggs into space, well then I will happily catch them with the reproductive sack on my upper flermin. I'm not the best at reading facial cues, but I can see that you're a little turned on.

Leonard: Okay, I'm going ask you one more time. We did the work together, let's present the paper together.
Sheldon: And I'm telling you for the last time, it's pandering, it's undignified, and bite me.

Sheldon: *knock knock knock* Wil Wheaton!
*knock knock knock* Wil Wheaton!
Wait, how many was that?

*Knock, Knock*
Leonard: Who is it?
Amy: Amy Farrah Fowler.
Sheldon: Darn, she found me.
Leonard: She's been here before.
Sheldon: The only flaw in an otherwise perfect plan. Now get my back, Jack.
Leonard: What do you want me to do?
Sheldon: Tell her I'm not here.
Leonard: Where are you?
Sheldon: I don't know. You'll have to devise a scenario that plausibly explains my absence keeping in mind that the key to a good lie lies in the details.
*Later, Leonard answers the door to Amy*
Leonard: Hi, Amy. Sheldon's not here.
Amy: All right.
Sheldon (to Leonard): Way to go on the details.

Penny: Okay. Hang on. Are you saying some day that you and Amy might actually get physical?
Sheldon: It's a possibility.

Leonard: Are you drinking whiskey?
Sheldon: Indeed. If I'm to participate in the social convention that is the "stag night," then I must embrace all its components, including tobacco, swear words and, yes, alcohol. Jeepers, that's yucky!

Sheldon: Listen to that! 'Stomp, stomp, stomp.' It's Wolowitz and his stacked heels that fool no one.

Sheldon: I don't understand your objection, Professor Goldfarb. Why wouldn't the Sonora Desert make a perfectly good Promised Land?
Goldfarb: Go away!
Sheldon: We could call it Nuevo Jerusalem.
Goldfarb: Please go away!
Sheldon: Said Pharaoh to Moses!

Sheldon: What's funny about Cylon toast?