I joined one of these a while back called Overgrown. It had the same "survive and do your own thing, don't get shot by a crazy person." It didn't last very long because, face it, people can only good off in a sandbox for so long before it gets boring. You need a story/goal/objective/means to an end. The idea is that we can goof off, but can actually do something if/when that gets boring. 

I have a handful of ideas if you're interested.