MMO Champion has a tip on a brand new festival that is probably coming to Azeroth (and Outland) in October. It's called Brewfest, and already in the 2.2 PTR patch files, they've found the ability to attack kegs, signal Dark Iron dwarves, race rams, and even eat sausages. Of course we're not sure that it's coming in October, but considering the similarity to the very famous Oktoberfest, the guess is probably not that far off. And of course whenever you mention brewing in World of Warcraft, you've got to mention the Pandaren-- could Chen and the gang, hope against hope, finally be making an appearance in Azeroth?
Boubouille also points out that the flying broom mount spells are in the game as well-- because they mention only giving one ride per mount, it's very likely that these too will be used on a temporary holiday, most likely Hallow's End. So sounds like lots of fun events coming this October-- I'm sure we'll learn more at Blizzcon.