YAMC? Yet another Minecraft clone??? Well Terasology (previously called "Moving Blocks") sure looks like one:
But besides looking like a pretty good YAMC, it actually promises to deviate from the boring Minecraft routine and mentions the pretty well liked games Dwarf Fortress and Dungeon Keeper as inspirations for its planned game-play :)
Code is under the Apache license, however the current pixel textures are non-free. But if this takes off, those should be relatively easy to replace with really free ones ;)
Oh and you can run it via Java directly from your browser (I had a black void as a world under Linux though... so your mileage might vary also).
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