I'm sure that this is some internet phenomenon which happened way back when, but this is the first I've heard of it.

Amazon.com (all hail the company) recommended a DVD called Bikini Calculus to me today. (No, I don't know why. Yes, my recommendations are all messed up because I have to test the site frequently. At least, that sounds like a plausible explanation to me.) Yes, it's two girls in bikinis. Giving a tutorial on the calculus of a single variable.

There's even a snippet on Google Video.

I'm undecided whether it's amusing, sexist, or effective. Probably all three to varying degrees.