Sometimes our dark side totally takes over. Witness the upcoming Warlock 16: Eleven Hells, where we call on two Planescape designers to open up a can of infernal mayhem and impress us with their malicious characters and locales, to name some of the archdukes and demon lords who rule there, and to provide treasures, lore, and adventure hooks to take your campaign into the Pit.
A guide to places most sane people never want to visit, coming very, very soon to a cosmology near you.