This is a sport named bossaball, which mixes elements of volleyball, soccer and gymnastics on a pitch of inflatables and trampolines (a big bouncy arena).
I think the shifted gravity ( trampolines --> G-force --> hang time ) added to the traditional ball game experience is very interesting.

It allows for a complete new range of techniques, team tactics and strategies to play and score.
Players are showing off juggling the ball.

The audience dances around the arena, cheering.
It's like one big crazy thing.
I think it's a great game idea, pretty innovative, fun to play and watch.
You can find more about it on http://en.wikipedia.org/wiki/Bossaball and http://www.bossaball.com/english.html