[url]http://www.reddit.com/r/CivilizatonExperiment/[/url]

There's a reddit forum for it, they are aware that the name is spelled wrong in the URL(character limit, apparently).  

The world can be played on normal minecraft, though it is an earlier version (1.7.10) and there are several plugins to aid in the experiment.  

The plugins are meant to make the formation of groups and civilizations necessary for survival, and the mods are, for the most part, very hands off.  Disputes are [i]supposed[/i] to be handled in game(very recently there was a large bit of drama that the mods got involved in, but it has since been resolved and is blowing over).  

I can't list all the civilizations here, but there's a Rapture-esque underwater one, a Feudal Japan culturally inspired nation, a floating sky nation, a secretive redstone tech based one, and many more bland ones.  

More in depth information can be found on the reddit forum.