Giant Shuffle Puck or Slip 'n Slide
We could use BBs as a frictionless surface for a giant shuffle puck table. We'd have to figure out a way to prevent the BBs from becoming moop. Higher side walls might work, but a nice solution might be to use steel BBs and a rolling magnet for cleanup.
This would be well lit of course.
Oooor.. how about a "slip n slide"?