Does anyone remember an old door game back in the BBS days called Cyberspace? It was almost more of an engine than an actual door, because once you set it up, it was up to you and your users to /dig new rooms, /describe them, define exits, create objects to populate them, etc. There were commands to make objects move from room to room, give them classic RPG character attributes, etc, so you could, essentially, create a game within the door of Cyberspace. I was considering finding the user docs for this door and recreating it in PHP. What does everyone think? Could be kind of interesting?