Here the 2nd site, that I find really engaging: Amped Up. Ampd Up is a flash version of the Playstation2 game Guitar Hero . It is not only fun among teenagers and adults, but also allows you to stick your face into the game (if you have a webcam).
The idea of adding your own profile to a game or movie (Verizon Actionhero campaign) is just great.
I can imagine that in the future some Onlineshops could adopt this technology. A fashion onlinestore could possibly allow site visitors to add a body or head shot and then let them try on clothes in a "virtual changing room".