There’s a video posted after the break of Peter Molyneux discussing Project Natal.
“Just about everything you think is the Holy Grail in design, throw it away and start again”, he said.
The designer talks about how Natal will create new sets of genres. The ones we are used to now, RPGs, sports games, etc., are “compartments that were defined by a controller” and Natal will create whole new compartments.
Heavy stuff. Have a watch.