Gearbox has posted the first five minutes of the Tiny Tina's Assault on Dragon Keep DLC for Borderlands 2. It's in the form of a video, but I guess you should've already known that.
The video shows how the campaign is a riff on Dungeons & Dragons, which sees the Vault Hunters (that's you) playing a Bunkers & Badasses campaign devised by Tiny Tina, sending these players into a world populated by enemies from fantasy worlds.
Tiny Tina's Assault on Dragon Keep is the fourth and final campaign DLC for Borderlands 2 and it's set for a June 25 release. It's free to all DLC Season Pass holders, and costs $9.99 separately for those without the pass. It'll be available on the PC via Steam, PLayStation 3, and Xbox 360.