The Stanley Parable. It's a game that really isn't like any other, which already contradicts the second sentence in this paragraph. This is the agony of writing about The Stanley Parable. In a few words, it's engrossing, hilarious, thought-provoking and maddening. All at once.
The first time I saw The Stanley Parable was at PAX. The developers had created a special "demo" of the game exclusively for PAX, with completely original narration and locations. Having now played the game in earnest, I can say that the demo, while having nothing directly to do with the title, taught me quite a bit about what to expect from the full title.
That made very little sense, I know. Perhaps it's best to say that The Stanley Parable is an experimental game. Simply enough, you play as Stanley, an employee who one day discovers that all of his co-workers have gone. Beyond that, things get murky. What followed in the hour and a half that I played in my first session was vastly different from any other game I've ever played.
The ideas that shaped the Stanley Parable are interesting enough on their own to provide a compelling experience, but it's the narration that elevates it. The writing is excellent, with great wit and though put into the innumerable lines of dialogue (monologue?) in the game. The Stanley Parable has numerous great moments, but it would be impossible to describe them without ruining them for you, the potential player.
My sentiments about the game and it's numerous spoilers make a written piece wholly inadequate. There is next to nothing more I can say about the game without coloring the experience for you. However, it will have to suffice, as I've no better way to communicate it.
The Stanley Parable really is an excellent game. If you haven't played it, you are missing something noteworthy. That's all I can really say. It's great, I love it. If you are interested in giving it a go, I'd suggest staying away from it's wiki page or any "Let's Play" videos. The Stanley Parable is best experienced when you know almost nothing about what to expect. I have so much more to say about the game, but they require me to address people who have played the game already. Perhaps we'll revisit it in a little while.