Well if you are one of the few who can actually log on to WoW right now, despite the extended downtime, you will notice that patch 1.12: Drums of War is now Live.
If you at at work, as I am, and unable to download the patch, you can read the patch notes here and find out what you are missing.
Of course the big changes are the rogue review, cross-realm battlegrounds and World PvP objectives, but I am particularly drawn to the UI enhancements.
And of course now that my level 50 warrior has finished both Uldaman and Zul'Farrak...they nerfed both instances.
If you are looking for patch mirrors try here.