It's Al Gore's documentary-style film showing one of the talks he's been doing around the world on climate change and global warming. I thought it (and he) were amazing, but it scared me too. It also motivated me. I am already very pro-active in terms of what I do and the impact it has on the environment, but that movie made me realise there is so much MORE I can do. It was really great, and everyone should see it.
I do tend to get pretty surprised if people haven't heard of it - climate change is so thoroughly in the zeitgeist at the moment - but it's great that places like this can bring its name to people who haven't heard, so they can go out and rent it!