Before Arkham Asylum, there was another Batman game in the works, this one tied to Christopher Nolan's The Dark Knight. At the time it was being developed by Pandemic Studios, the developer behind the original Star Wars: Battlefront, Mercenaries, and The Saboteur. Unlike Arkham Aslyum, Pandemic's Batman game was never released.
In this video Unseen64 uncovers the strange, troubled development of the game. It's an utterly bizarre (U2's Bono plays a pivotal role!), kind of tragic story that you should definitely take the time to watch if you're interested in either Batman or game development in general:
[Correction: We have corrected an error that misattributed the video. The video was created by Unseen64. We regret the error.]
[Source: Youtube]