If BioShock Infinite was your thing, you're in luck. Last week, Clash in the Clouds, the first bit of DLC was released. It wasn't a story oriented piece (those are coming later), instead you're getting what's basically an arena combat mode. It plays fairly similar to the Horde mode found in the Gears of War series - go up against wave after wave of enemies in four different arenas. While, the arenas are designed after areas from the single player of Infinite, they're freshly made with this game mode in mind.
The interesting (and the thing that has me the most intrigued) is the reward system. It was fairly easy to find something comfortable in the single player and stick with it, never really allowing yourself to experiment with the different combinations of vigors and weapons. In Clash in the Clouds, you're challenged to try new things to clear the ribbon challenges to unlock stuff in the Columbian Archeological Society, which gives you access to new Voxophones, Kinetoscopes, concept art, and more.