I just finished watching Dark Days [1], a facinating documentary on a very unique neighborhood—one that existed in the subway tunnels of New York City. Granted, these were formerlly homeless people, but can you really call them homeless when they made their own homes (okay, huts made out of found plywood) and had electricity (and at one point, running water)?
Equilly fascinating was the making of the documentary, where the film maker, Marc Singer [2], managed to rent camera equipment, bum B&W (Black and White) film, use the subjects of his film as film crew (and he himself had no experience in making films) and solely on the subject matter of his film, get it developed, edited and scored for an incredibly low amount of money, where it went on to win several awards at Sundance [3] 2000.
[1] http://www.imdb.com/title/tt0235327