Go! Power Team!
The first game to be demoed was Go! Power Team! which I first ran at the JOIN Local Multiplayer festival in Berlin last year. For the uninitiated, four players take the role of "Rangers," each of them wearing a dedicated power-belt (a modified Android tablet connected to the main computer over WiFi). One player is selected from the crowd to the the "defender of the galaxy," tasked with fighting off monsters by pressing the coloured power-belts in the right order.
Every time a new monster appears the rangers are given a new command by the computer, which will tell them to lie on the floor, form a conga line, or hi-five the audience, among other things.
The idea is that the rangers are not on the side of the player, nor working against them, but acting of their own accord. Typically the rangers themselves will focus on performing, to make the audience laugh or to one-up each other with their outrageous interpretations of the commands. This is one of the benefits of keeping the rules of a game loosely-defined!