Convert your home or local derelict building into a interior race track by installing a twin railed guide system that snakes and twists around the building's walls with chair/stair lift swivel seats attached.

Rig up the rail system to the local power grid, volunteer two people to control the speed of the would be pokadot nerf gun chair jockeys. With game pads in hand, they fly along their guide rails attached to opposite walls attempting to nerf each other.

Each chair is also equipped with joysticks, electronic and mechanical braking systems,whisper mode and a speedometer (for those that choose total control rather than relying upon someone else)

Could be fun by bringing a little of an outdoor experience to this by having the rails sweep out of a top floor window then back through another then hurtling head first down a wide open spiral staircase.