If The Beginners Guide goes on sale, grab it. It isn't much of a game but rather a tour inside of the mind of the guy who made The Stanley Parable. Its about 2 hours long and is quite emotionally gripping. Story is brilliant in the fact that there really is no characters except the narrator (Davey Wreden).
It has seen a lot of popularity since its release and i imagine it will go on sale since it had quite a strong release which tapered off to a plateau and will only really sell while people are still talking about it since it is pretty niche.