In the next patch (3.1) a whole new spin to the game will happen when Blizzard implements a new world event named the Argent Tournament . Details are spare but you'll be able fight for a faction of your choosing in the new mounted combat system. This will bring new daily quests, new rewards of every type, and more achievements!

The tournament will be on the PTR in the near future (this week we're all hoping but it might not be there at the start) and you'll find it in Icecrown once it's there.

You can read the original post by Zarhym here.