Baldness is serious business--to the tune of millions of dollars every year spent on surgeries, special sprays, and hair pieces. Aderans, the Japanese equivalent of Hair Club for Men has a neat service called HairTry that lets you upload a picture of your head to try on various hairstyles without having to leave your couch.
It takes a 2D photo you've uploaded and processes it for 3D, adding facial gestures and eyeballs that follow your mouse around as you navigate the site. The 3D effect is far more believable than a still image, and even gives you a little back and forth sway that shows off the sides. If you've used Gizmoz or BigStage this is very similar. However outside of those two, and virtual make-up site Taaz (coverage), this is one of the only services I've seen apply the technology to a business.
In addition to hair, the site offers a small selection of eyeglasses, which has been done elsewhere, but is a nice touch considering they've already got your face ready to work with.
The site is entirely in Japanese and runs in Adobe Flash, so you can't use Google Translate on it. In light of that, I've made a quick tutorial of how to upload your head, pick hairstyles, and export it into an amazing image file you can use on your social network of choice: