The Big Bang Theory, Season 2

Sheldon:
[about Leonard] My theory is that his lack of focus stems from an overdeveloped sex drive.

Beverly Hofstadter:
Oh, I don't know where he would have gotten that. Aside from a pro forma consummation of our marriage, his father and I only had intercourse for the purposes of reproduction.

Sheldon:
That seems a fairly efficient arrangement.

Beverly:
Yes, we think so. We've both done papers on it. Mine from a neuroscientific point of view and his from an anthropological. Mine, of course, was the only one worth reading.

Sheldon:
Of course. I would very much like to read about your sex life.

Beverly:
Well, it's all online, or you can order it from the Princeton University press.

Leonard:
Here is your tea, mother. So, what are you guys talking about?

Sheldon:
The frequency with which your parents had intercourse.

Leonard:
Swell. If you are lucky maybe she'll show you the PowerPoint presentation.

[Sheldon looks thrilled]

Beverly:
I'm sorry, it's on my other laptop.

Sheldon:
Awwww…