It's called "ShowerShock," apparently

James Lileks reports,

A few months ago we revealed that a scientist had invented the caffeinated doughnut. I don't have the column at hand, but I fear I went the Way of the Hack, and said "What's next, caffeinated shampoo?" or some such grindingly unfunny observation. If that's what I said, well, I was close. Caffeinated soap has been invented.

No, really.  I don't think he's kidding.  You're supposed to absorb the caffeine through your skin.