In my recently completed Black Hack campaign, I had a mysterious Door in the middle of the wilderness called the Door of Mystery. My players never dared open it.
If they had, and stepped through, I had a small basket filled with OSR zines and books next to my chair. Each book had a different OSR setting. My plan was to pull a zine out of the basket at random, and that's where the players would end up.
Some of the options were: Night Land, The Rainy City, B/X Mars, Planar Compass, Carcosa, Gathox Vertical Slum, Ultan's Door, and Dolmenwood
