Citadel Studios will be hosting what they are calling the Night of the Living Dead event over the Halloween weekend. Although, I think they should call it Nights of the Living Dead, seeing as how it will transpire across the course of four evenings:

Starting Thursday October 29th at 8PM EST (12:AM UTC)

Additional Event Times – We will open the Halloween server for two hours at different times each day during the weekend in case you miss the main event.

Friday, October 30th 6:00PM EST (10:00 PM UTC)
Saturday, October 31st 12:00PM EST (4:00 PM UTC)
Sunday, Novermber 1st 3:00PM EST (7:00 PM UTC)

This will be a PvE-focused event, in which players take on the role of the undead:

Ever wonder what it would be like to be on the other side? Well this Halloween weekend, playtesters will get a chance to spawn as undead in the graveyard and protect it from the evil humans who are trying to rob the graves! You start as a ghost trapped in limbo. From there you will spawn into one of the many denizens of our very own Eldeir Cemetery. When you arrive, you find yourself faced with a constant onslaught of human graverobbers. Killing humans gets you additional spawn points to spawn into bigger and better creatures each with their own special abilities like a dropping a nest that spawns baby spiders, hell portals, werebat packs and more.

It would seem that the first event — which was held tonight — has already ended, but there are still three more times during which you can jump in and torment those bend on robbing your grave.