The back-story is that this is a mining colony on Mars – the arena is an ancient Martian city that’s been turned into a place for the miners to live – with a glass canopy enclosing the atmosphere. Since it’s a low gravity world, miners can get around on a variety of human-powered flying machines – bicycle-powered helicopters, giant mutant eagles, jet-packs, etc. For fun, they play a game that’s a bit like 3D football – flying around the arena – grabbing the ball using force-field “grabbers”…using huge ore buckets on cranes as goals…you get the idea.