This idea is in its infancy. I haven't playtested it at all. Hell, I'm just making up the example now. I had this thought last week on vacation (sitting by the pool has its perks...) but I'm just getting around to writing it up.
The idea is based on the premise that megadungeons should change over time. The players enter a room, maybe they kill a monster there, take its stuff, etc. Something should be different the next time.
Coming up with those "differents" is sometimes very hard. The idea that I had was a kind of flow chart or checklist that DMs could use as the room evolves through the exploration of the megadungeon. When a "state" is used, you check it off (maybe date it) and move to the next state next time.
Here's an example (very crude)
[ ] Room has 2 orcs (AC 6, HD 1, HPs 5,4, AT: 1 club, 1d6) The orcs have 21 sp between them. There is a crude table, two piles of straw for beds, 2 dirty blankets.
[ ] The room is strangely empty and very, very clean. Not even any dust. No furniture. Nothing.
[ ] A pentagram has been scribed on the floor in pink chalk. Stubs of red and black candles remain at each point.
[ ] There is a bloody pentagram on the floor of the room. Deep gouges have been made in the stone. A single elvish shoe (dainty and expensive) badly torn and bloody lies on the floor.
So, the GM immediately has a narrative in the room. Things can change. Of course, not every room would have a "timeline" or narrative. Just enough to keep the megadungeon "alive" in the minds of the players.
Additionally, if the players impact the development of the events, the DM will need to improvise. In the example above, perhaps the PCs damage the pentagram deliberately during their 3rd visit to the room. If so, then the 4th visit makes total sense. If they completely obliterate the pentagram, maybe the wizard does a poor job re-doing it. If they just scratch a line, well that makes sense too.
Anyway, I can see myself writing up some "narratives" for certain rooms if I ever get around to making my megadungeon.
What do you think?