I just returned from seeing the movie Precious (2009).
I had heard from many people that this movie was difficult to watch - a number of people had to leave halfway through it. I consider myself to be an extremely emotionally stable person, and I sat through all 110 minutes of it. The end killed me - I'm still a mess, half an hour later. I cried the whole way home. This movie should be required viewing for everyone over the age of 18. It's amazing, powerful, and beautifully presented.
The trailer doesn't even begin to do it justice. Just go see it.