Microsoft flirted with this years ago-- Windows Media Center edition came with little lifelike avatars that could move according to what was going on at the time (I know music was an input but I think there may have been others). The effect was lightweight and I'm not sure why it didn't take off... maybe it was the fact that one of the avatars was a cute female and her dance moves were a big turn on. Maybe too many wives complained. Maybe male productivity took a nosedive.

Or was it just me?