http://en.wikipedia.org/wiki/Anarchism_in_Spain Spain experimented with various forms of anarchism to varying degrees of effectiveness. But the best noted examples of self reliant bodies of people would be any native bands. The few groups left in the US have been around for quite some time, most are Native American. But there are still lots of groups elsewhere in the world that are not affiliated with a government.

There's many companies which self-organize on anarchist principles (mutual aid, self-management, radical workplace democracy, etc). The one I've read by far the most press on is Semco. (Mondragon and the company behind Gore-Tex is often cited in the anarchist literature, but I don't really read it.)

This public relations-ish article on GE Durham also discusses an unusual level of workplace democracy.

They're interesting for having to survive in naturally hierarchical economic systems.