Well, since I can't seem to post to the other site here's my idea:
This idea plays off the lost room mini series if anyone has seen it. Basically, dungeons as intelligent malevolent beings are created through a single act of evil and depravity. This act can be small, say a father striking down a child or involved like a murderer slaying a whole group of people there. These usually happen in small underground places such as a cave entrance, a basement, a sewer. This act spawns an evil sentience that the place remembers. As it sits there, it grows. The items from that act, whatever remains are the power that create it and are drawn down deeper into this growing darkness. Passages, tunnels, and traps grow here all related to the items creating them and the act itself. A man was stabbed, then lots of spike traps are going to appear to stab those who enter. Maybe the monocle he was wearing takes over another part of the dungeon, creating elaborate visual puzzles and rooms of glass. As the dungeon grows, so do these items power. They though cannot leave the dungeon, and must be destroyed in order to destroy the dungeon. But within the dungeon, they have powers of their own. They also have sentience depending on how long they’ve been there, with some items even using creatures that have stumbled into the dungeon to protect themselves and wage war on others. The goblin tribe that fell into the glass area of the above dungeon for example, now has their leader who wears the monocle and demands they do anything in their power to get the dagger on the other side of the dungeon and destroy it. The players have to brave these various groups, the dungeon, and the items in order to destroy it. Only after all the sentient items are destroyed will any trace of the act exist and the dungeon collapses on itself.
Just how I would run a players traveling around fighting sentient dungeons campaign. Allows for all sorts of inter political fightings in the dungeons as well as groups to ally with against other groups in the dungeon as well as crazy dungeon design magically based off of whatever items were used in the evil act.