Old Boy
Korean film, subtitled. Great movie. A guy gets randomly abducted, and imprisoned for fifteen years. He doesn't know who did it or why. He's realeased without warning, and tracks down who imprisoned him, who then challenges him to find out the far more important question of
why.
The fight scene in the corridore of his prison, in which Oh Dae-Su takes on a dozen or so men armed with lengths of timber, he himself having only a hammer, is the best I've ever seen.
Be warned, the twists at the end, while very unexpected, are quite disturbing - don't watch if you have a delicate moral sence. Otherwise a great film.
Gray, I never know Korean was such a great language for shouting threats in!

Or maybe the guy who plays Oh Dae-Su is just that good an actor.