Halloween 2001 was the best GM event I ever participated in, and it really wasn't hosted by actual GMs. Just the fact that certain zones could become radically different brought some spice to the game. Kithicor Forest brought out the nasty high-level folk one or two halloweens before, but it wasn't quite the same somehow as the spontaneous influx of players running around in complete mayhem.
I died multiple times trying to hold nice items for low level and new players who were baffled by what was going on. East Karanas and Rathe Mtns. were the most fun. Esp. with the uber Drakebone trotting around the zone fearing and nuking people. Lots of corpse runs there too, but they were FUN.
Something EQ needs desperately, is REAL people running some of the "boss mobs" behind the scenes. That is about the only way this game would really become more interesting. Otherwise, it is just a lot of camps.