World of Warcraft is having a spot of bother with a rather unpleasant Old God, N'Zoth, now that the latest update, Visions of N'Zoth, is live. Heroes of the Horde and Alliance will need to fight through nightmarish visions, corrupted zones and a new raid. Expect tentacles.
To get up to speed, check out Steven Messner's interview with senior game designer Jeremy Feasel, exploring the changes that the 8.3 update brings about. They're pretty significant, leading to the conclusion of an expansion that's had a lot of ups and downs. Blizzard's put together a hub with all the new stuff in one place, so you can check that out before you dive in.
Visions of N'Zoth also adds a pair of new Allied Races to the roster, letting you make a Mechagnome for the Alliance and a Vulpera for the Horde. I'm a big fan of the Allied Races, as someone who is addicted to alts, but god help me I can't be arsed with the grind to unlock them. It's miserable.
Good luck with smacking that Old God about.