I have some more serious thoughts in my head about WoW, but they're not congealed yet, so instead, let's talk about Halloween. Blizzard has incorporated a variety of events related to seasonal holidays. We actually just had brewfest a couple of weeks ago. I'm now a member of the Brew of the Month club and a brewmaster. W00t!
These events tickle me with their allusions to the real world while taking advantage of the game world. For Halloween, you can go trick or treating at all the inns. There's an achievement to get candy from the pumpkin buckets at every inn in the world. You can also "trick or treat" once an hour with an innkeeper. Tricks include getting turned into things like bats, frogs, and ghosts. Treats can be candy, masks (which need to be collected for an achievement), or other fun items like toothpicks. There's also a headless horseman who terrorizes a couple of towns by setting the buildings on fire. Characters form a bucket brigade to put out the fire and become a hero.
You can take down the Headless Horseman by taking 4 of your best friends into the Scarlet Monastery, calling out the horseman and then killing him. It's a fun fight, especially when his head disconnects from his body and you have to chase the head around. The horseman drops several unique items, some of which are needed to get the Hallow's End achievement. There's a pet pumpkin and a special helm that are especially coveted. There are also several rings, a broom mount (seen in the picture above), and a horse mount (which is very rare).
Throughout the season, you see people running around with pumpkinheads, as ghosts or bats. The towns are decked out in Halloween decor, and the whole scene generally puts you in the Halloween spirit.
WoW.com has the lowdown on all the achievements for Hallow's End if, like me, you're an achievement whore.