The Bethesda Blog announces plans to release Dunwall City Trials on December 11th for Windows and consoles, offering new content for Dishonored, Arkane's assassination game. They offer a slideshow of screenshots from the DLC, and here's word on what it will offer from its announcement:

Dishonored: Dunwall City Trials, being released in December for $4.99 (or 400 Microsoft Points), will include 10 challenge maps that will test and track your combat, stealth and mobility skills. Ten distinct trials await challengers – including an arena battle against waves of enemy AI, a gravity-defying run of drop assassinations, and a race against the clock. Dunwall City Trials also features a whole new set of achievements and trophies as well as a global online leaderboard that will establish the greatest assassins for each challenge.