Hallow's End Arrives

Observed by both the Horde and the Alliance, Hallow's End is the celebration of the break between the Forsaken and the Scourge. Many tricks and treats await adventurers seeking holiday fun, including defeating the Headless Horseman, visiting inns and cities for fun items such as masks and costumes, and eating way too much candy in one sitting. Hallow's End begins October 18 and continues until October 31.

http://www.worldofwarcraft.com/info/events/hallowsend/

If you're running into any issues with the event, please feel free to report them. In the meantime, there is a thread on currently known issues or concerns in the Customer Service forum here:

http://forums.worldofwarcraft.com/thread.html?topicId=27291816177&sid=1