Lately I have been playing Minecraft on a unique and server called Civcraft. It started as a social experiment by some anarcho-capitalists from Reddit, then branched out to other political communities. In contrast to most large Minecraft servers, which are either admin-run plutocracies or hardcore PvP tournaments, Civcraft uses special mods and hands-off administration to put the power in the players' hands and let them shape the world themselves. The players, in turn, exercise the great pastime and challenge of mankind: Civilization.
Without artificial rules and limitations, it is up to the players to decide how they will play and who they will be. I, for example, am the benevolent king of Gondolin, a hidden libertarian paradise with a Middle-earth theme. I'm also the new owner of the skeletal remains of one of the server's oldest cities, and the abbot of a charitable monastery. You can be anything you like. We have libertarian socialists, communists, republicans, of course AnCaps, and even villainous griefers who flirt with permanent imprisonment in the End. In two months, cities have been built and abandoned, wars fought, alliances forged, trust betrayed. It's a Minecraft world unlike any other- a simulation of real-world politico-economics among competing ideologies.