Recently there was some discussion about ways Squeak might take over the 
world, of which I think Croquet/Cobalt 3D was one possibility.
Distantly related to this, I was blown away by the videos linked below, 
which present two methods of cheap tracking interacting with an 
off-the-shelf 3DTV.   I felt there might be some fantastic synergy 
between this and squeak. Maybe in a while I'll be capable looking into 
it further myself - but for now, just sharing a random inspiration.

cheers, Ben