If you're attending PAX this year, make sure you head over to the Warner Bros. booth. There, you can register to win a 100% free, brand new Batman Arkham City Xbox 360 Slim. As of now, this one of a kind custom 360 designed with Arkham City imagery will only be available at PAX in Seattle, Washington. Even if you aren't a fan of the game or of the Xbox, go ahead and register. If you win, you could make some BIG bucks with this on the good 'ol Ebay.