Arcen Games recently released their first game, AI War. It's available directly from them, along with a demo version You can also download it via Impulse, which is Stardock's equivalent to Steam. ("Steam Powered", "Impulse Driven". I see what they did there!)
I am highlighting (not reviewing) this game mainly because it's the first selling game, indie or otherwise, that is actually built on top of SlimDX. It's been out for some time, and we've been aware of it, but for some reason we only just noticed that it's an actual title rather than just another hobbyist pseudo-game. Visually it's not terribly sophisticated, but that's simply not the point. The UK Gamer blog has a review, for some more discussion of the actual gameplay.
What is interesting about AI War is, well, the AI. Since I haven't actually played the game yet, I can't actually tell you how effective it is. But as a strictly technical piece of work, it's really quite impressive. The guy behind the game is Chris Park, who has his own blog. He's written two entries about the AI so far (One, two), and more are coming. There's lots more tech information over there though (and also discussion of game design), so I'd recommend skimming the blog. It's similar to a post-mortem, except he's only talking about the positives so far. That's a hint, Chris!
I'm hoping to see more games rolling out on top of SlimDX. XNA's done a lot to further the case for managed games in general, but with support for the new 10 and 11 APIs, 64 bit, and all sorts of other things, I'm eager to see what people can do with our tools as well.
Chris wrote a response to this post that I like to read. Possibly because it's very flattering about my project. I just wanted to clarify that his is the first selling game built on SlimDX. We're a lot more popular for non-games work, actually.