Sauerbraten (video game)
Maps are made out of cubes, which can be made longer or shorter and can be reshaped. These cubes can be mapped out easily, using the in-game editor. This means that both map-makers and players can make very big, detailed maps very quickly. This is not like other games such as Quake, where you need a lot of effort and bugfixing work to even get the map to work.