Eidos have announced two free downloadable content packs for their hugely successful Batman: Arkham Asylum, the first of which arrives on the Xbox LIVE Marketplace tomorrow.

The first challenge map pack, titled 'Insane Night', contains one Freeflow Combat and one Invisible Predator challenge map. The 'Totally Insane' Freeflow Combat map sees Batman attempting to stop fast moving lunatics from escaping the asylum's secure records facility, while the 'Nocturnal Hunter' Invisible Predator map takes place within the Arkham grounds and will require you to use watchtowers wisely to take out the Joker's tougher henchmen.

The Insane Night challenge Map Pack will be available Thursday September 17th, and it's free!

The second DLC pack is titled 'Prey in the Darkness' and will be available the following Thursday September 24th, also free!