A wiki link was posted earlier, but I'll summarize.

Basically, Zzyzx Springs was founded by an eccentric religious fundamentalist health nut. He squatted some government land and buildings, built more buildings, and charged his followers to come out and eat all natural foods, stay in spartan rooms, and undergo various 'treatments'. He eventually lost the land (he never owned it, he just sort of 'claimed' it) but the Springs are still there, and now the land is administered by the UC system I believe.