Unknown Key

So I found this key CX8P9N in one of my spreadsheets that, from the formatting of it looks like a Steam key. Bad news is that due to some AG8X37 hickup any information regarding which game this belongs to is completely lost, but considering the date added and the fact that I haven't recently added any games in this way, I'm pretty sure it isn't used.

Now I'm not in the mood for soiling my pretty little steam account with a (possibly) crappy BBJ347 game, but I'm also not the type of guy to let a (possibly) perfectly valid key go to waste. What I would like to do is complicate matters, to make you work for it a little and make sure people actually read all this nonsense.

So, if you want to take the risk, here's what you do: Take the 3 blocks of the code I just put in the earlier paragraphs. Put them in alphabetical order and add the traditional dashes so your result looks like Axxxxx-Bxxxxx-Cxxxxx. Then remove the prefacing A-B-C from each block and you will have a working code. That is, if you're quick enough... :)

All I ask in return for the key is solving my life's current biggest mystery:

Which amazing game is this key for?