Dead Rising 3 Arcade Adventure was announced at during Microsoft's E3 press conference. It's already out, and the DLC allows an arcade experience with players able to cosplay as their favourite Capcom characters in the Dead Rising zombie sandbox.
Update
As revealed on Xbox Wire, the new DLC is going to be a four-player co-op mode for Dead Rising 3, although we didn't catch the full awesomeness of the title the first time around. Here's the blurb direct from MS:
Capcom Vancouver reignited the zombie apocalypse with "Super Ultra Dead Rising 3 Arcade Remix Hyper Edition," an all-new, four-player, co-op arcade mode launching today that lets fans play as past "Dead Rising" heroes or cosplay as their favorite Capcom characters while battling zombie hordes and giant bosses in crazier ways than ever before.