The Act of Killing - it's hard to even describe the premise. Its a present-day (2012) profile on participants in the 1960s mass killings in Indonesia. An absolutely brutal look into human nature.
It is hard to describe this doco in any way that does it justice. Fascinating, compelling, horrifying, disgusting, surreal. The breadth of discussion it opens up both on the individual events it covers and the implications for humanity.
I have never seen a movie like this before and I doubt I ever will again. It is in a total category of its own.
I watched that shortly after release. Very memorable. It was quite bizarre to hear someone freely discuss his day job of murdering people in such a casual context.