Penny: Look, can't you just let him play with you until bedtime?
Leonard: We're not playing. This is real work.
Howard: We're going to be hundred-aires.

Howard: You know, I'm really glad you decided to learn Mandarin.
Sheldon: Why?
Howard: Once you're fluent, you'll have a billion more people to annoy instead of me.

Bernadette: Maybe we should get one of those machines to help her up the stairs.
Howard: You mean a forklift?

Sheldon: Sheldon Cooper does not cry.
Howard: That's true, you'd rust.

Sheldon: I'm not saying that all senior citizens that can't master technology should be publicly flogged. But, if we made an example of one or two it might give the others incentive to try harder.

Raj: Ooh, Leonard is going all alpha nerd on Sheldon's ass.

Leonard: I had a great idea. Do you know how we're always having to stop and solve differential equations, like when you're doing Fourier equations or using the Schroedinger equation?
Sheldon: Howard doesn't, he's only an engineer.