For $14.99, you can download the indie title "Limbo" for Xbox 360, PS3 or PC. I've never really browsed the indie game section of the marketplace, but after positive reviews, I had to give it a try.
You control a young boy, pressing through a dark and disturbing world. Booby traps, giant spiders and rogue machinery serve as obstacles that you must overcome. You have no explanation as to why you are traversing this eerie world, but it becomes quite clear, you need to get the hell out of there.
Limbo harmonizes visuals and sound very nicely, in a gloomy way. The entire game is black and white, but there is an incredible amount of detail on everything. There are no cut scenes or loading scenes, just one continuous game with an unlimited amount of lives... which is good, because the puzzles and traps can be quite challenging. And they get more difficult.
It doesn't take every long to finish the game, roughly 5-6 hours. It will take you a lot more time to find all the hidden gems though. Very cool and disturbing game.