Amy: My old scarf.
Sheldon: You wore it the night we went ice skating, remember?
Amy: You mean the night that I went ice skating and you stood at the rail Googling the symptoms of hypothermia.
Sheldon: We made one heck of a team, huh?

Sheldon: When was the last time you had your menstrual cycle?
Penny: Oh, I'm not answering that Sheldon.
Sheldon: I'm going to say in progress.

Sheldon: What could I possibly have done to offend Mrs. Vartabedian?

Sheldon: I don't watch you twenty-four hours a day. I don't know what you do.

Sheldon: Oh, you don't need to worry about her. She's brilliant and attractive. She can do way better than Leonard.

Sheldon: I feel renewed. I'm ready to deal with any changes that come my way. [sees Penny] Your hair is different. You changed your hair. I can't take this. I'm out.

Sheldon: (Knocking on Penny's door early in the morning). Penny, Penny, Penny!
(Penny opens the door).
Sheldon: Good morning.
Penny: Do you have any idea what time it is?
Sheldon: Of course I do. My watch is linked to the atomic clock in Boulder, Colorado. It's accurate to one-tenth of a second, but as I'm saying this it occurs to me once again your question may have been rhetorical.

Leonard: New neighbor?
Sheldon: Evidently.
Leonard: Significant improvement over the old neighbor.
Sheldon: A 200 pound transvestite with a skin condition, yes, she is.

Raj: You can't wear the hands on the date.
Sheldon: Hulk sad!

Sheldon: You know I'm in such a good mood I'm actually finding your tenuous grasp of the English language folksy and charming today.

Leonard: I'm gonna invite her (Penny) over. We'll have a nice meal and chat.
Sheldon: Chat? But we don't chat, at least not off-line.

Sheldon: Penny.
Penny: What?
Sheldon: I can't sleep.
Penny: Maybe that's because your hole is still open.

Sheldon: Excuse me. You're misusing the word 'ho'. It's an interjection used to call attention to a destination, not an object, as in 'land ho' or 'westward ho'.

Penny: Son of a bitch!
Leonard: Penny's up
Penny: You sick, geeky bastards!
Leonard: How did she know it was us?
Sheldon: I may have left a suggested organizational schematic for her bedroom closet.
Penny: Leonard!
Leonard: God this is going to be bad.
Sheldon: Good bye, Honey Puffs. Hello, Big Bran.

Sheldon: I never joke about safety.