The Revers RPG is a rules-light and lighthearted role-playing game where players don't get to decide what their characters do--but they do get to decide whether they succeed at doing it. Players grab a handful of mixed marbles (black, white, and a few red) and then as the Game Master outlines the narrative, characters determine success or failure by playing (discarding) either a white or black marble, respectively. Another player may then play a red marble to reverse the decision. Players don't get to grab another handful of marbles until they've played out the first handful--including red ones.
Character creation is exceptionally simple and involves defining Attributes and then arranging them across a dice number spread. When an action is taken, the player rolls a dice, finds the Attribute, and must proceed to resolve the situation in that manner (e.g., using that Attribute). The GM narrates the campaign; the players narrate the action scenes.