Private realms, instanced dungeons, mission areas, content on demand systems, Auto-Content Generated (ACG), modular hallways... many names have been given to this unique invention which came into the massively multiplayer online gaming scene with Anarchy Online in 2001. Instantly available personal dungeons with "infinite" variations in looks and size, tailored to each person's or group's level and preferred settings... it goes without saying that this was a quantum leap feature in MMOG design when it first came out. As more and more MMOG games develop similar systems of their own - and surprisingly enough, some MMOGs at E3 this year claimed they will be the first to have private realms... even though they're not yet out the door :) - it's clear that this system is (almost) essential for any MMOG developer wishing to produce the ever-popular dungeons in a fast, reliable, cheap and instantly testable way. After all, such games are played for thousands of hours, and all that shiny static content and NPC quests are "eaten up" faster than you can imagine.