From Everquest2.com:
SOE Trick-or-Treat Event is Here!
It’s time to trick-or-treat in your favorite games*! Today through October 31, 2011, get treats and tricks when you visit your participating games each day. For EverQuest® II and EverQuest® II Extended, check the mailbox for your tricks and treats!
For more details visit www.soe.com/trickortreat.
Participating games include: EverQuest EverQuest® II,;EverQuest® II Extended, Free Realms®, Star Wars®: Clone Wars Adventures™, PoxNora® and Magic : The Gathering – Tactics™
Note: This actually started on Friday, Oct 28, 2011