"Steambots and Megaswords". A fast-paced, spontaneous roleplaying game inspired by the Final Fantasy series of video games as well as "Avatar: The Last Airbender" and other animated shows and movies. The game combines narrative freedom in character scenes and combat maneuvers with elemental powers, Soulbound Weapons, and the summoning of Eidolons to allow you to create your own stories and action scenes. Winner of the 2011 Indie RPG Award for Best Free Game.
In this game, the responsibility for the group's enjoyment is evenly distributed among all of the participants. As long as something is reasonable, the players can describe it as existing in the story. If they're in a forest, they can introduce sticks, stones, wild animals, and so on into the scene. If they are in a city, they can describe cracks in the street, ladders at the side of a building, and anything else that could be found in such a place, even if it's unlikely. Notice that the standard is reasonable, not probable. As long as it's possible and its introduction doesn't ruin other players' fun, it should stand.