Please recommend some other documentaries.

We all know of the big documentary releases but it's often ones like this that are easy to miss unless you look at the tv guide, get lucky whilst changing the channel or get it recommended. So I'm looking for some recommendations, obviously not stuff like Sicko or March of the Penguins! I can recommend one that I saw recently, Which Way Home. A doco following some children travelling through Central America on the tops of freight trains trying to make it into the US.