Here are a few i like:

City of God (although i'm sure most of the class has already seen this, it's still a great film, or perhaps we could read the book. There is also a film based on the same thing City Of Men)

 Born Into Brothel's (Documentary "A tribute to the resiliency of childhood and the restorative power of art, Born into Brothels is a portrait of several unforgettable children who live in the red light district of Calcutta, where their mothers work as prostitutes.")

 Life In Debt ("By combining traditional documentary telling with a stylized narrative framework, the complexity of international lending, structural adjustment policies and free trade will be understood in the context of the day-to-day realities of the people whose lives they impact.")

  Children Underground ("documentary follows five homeless children in Romania, where the collapse of communism has led to a life on the street for 20,000 children")

 Devils Playground (Don't really know about it but it's about the Amish teens, what happens when they're thrust into the "English" world)