Terasology

Terasology is a super extensible open source voxel-based game. Born from a Minecraft-inspired tech demo, it is gradually becoming a stable platform for all sorts of gameplay settings in a voxel world.

From the ground up, Terasology was built to be a super hackable and modular game. It hosts a large number of modules under the Terasology organization and many more which are maintained by individual enthusiasts.