Dishonored: Dunwall City Trials releases in December for £3.99 / €4.99 or 400 Microsoft Points simultaneously on PC, PlayStation 3 and Xbox 360.
It includes 10 challenge maps each with 10 distinct trials designed to test your combat, stealth and mobility skills. These trials include an arena battle against waves of enemy AI, drop assassinations and a race against the clock. There are new achievements and trophies and a global online leaderboard.
Source: http://www.eurogamer.net/articles/2012-10-25-first-dishonored-dlc-has-a-wave-based-arena-battle
So what do you think of that?

(Only discuss the first DLC here, please.)