Would it be done in magicaVoxel?
My idea would be something like the David tower in Caracas, where everyone get a space and start to put stuff in in, or build stuff. The great stuff would be featured on the the roof top every saturday.
Motocycles and others vehicles in the parking etc.... everyone can hang around for 1 day as long as he brings some voxels , like 3 oranges or a broken chair! and aquires space as he bring some more important contribution to the space, then there is the possiblility of trading stuff, find services, repair shops, furnitures,
It would need some kind of syndic or boot to attribute the space floors,
Also some little TV scween on the ground floor showing ,what is happening in the floors , for the visitor not getting lost in the huge building...
How does this sounds?
It should be weapon free, (too much weaponry in the 3d world!!!)