Blue Valentine.
I didn't know what to expect, and was "pleasantly" surprised. I use quotes because it is not a pleasant movie, in fact it is an unpleasant, uncomfortable movie. But it is a good movie, and I wasn't necessarily expecting it to be good. It is one of those movies that I keep thinking about, even though I saw it about a week ago.
I'd probably give it 5 stars (out of 5).