A new Scenario has been enabled for testing today. Arena of Annihilation.
Here's the map of the place and below, you'll find a short video depicting everything about it.
Click on the image to zoom in.
The place looks similar to Trial of Crusader.
Arena of Annihilation is the same as Ring of Blood (Burning Crusade) or Crucible of Carnage (Cataclysm). You have to defeat bosses in order to succeed. It has three stages. The video below tells you more.