Roll 1d6I really like this table because it mechanizes the process of keeping a megadungeon "alive," which is, I think, a key feature that distinguishes it from smaller, "lair" type dungeons. When I started work on Dwimmermount, I decided that, in addition to this table, I needed another one. The reason was that, while Sham's table is great for determining whether or not a room that once held six orcs whom the PCs slew has been re-occupied in the interim, it says nothing about the occupied rooms the characters haven't yet explored.
2 Monster and Treasure
3-6 Empty (1 in 6 chance of concealed treasure)
Why would that matter? Well, one of the premises of the Dwimmermount campaign was that the Thulian mountain fortress had been shut off from the world for several hundred years beforehand. The PCs are, for various reasons, the first outsiders to successfully enter Dwimmermount since the fall of the Thulian Empire. However, they wouldn't be the last. Once word got out that the PCs had done the seemingly impossible -- returned alive from the megadungeon and with loot -- it'd only be a matter of time before others followed in their footsteps. Thus was born the Rival Adventuring Parties table.
I roll on the Rival Adventuring Parties table every time the PCs return to town, but, unlike the restocking table, I roll once for every room the PCs didn't visit, modified by +2% -- it's a percentile table -- for every time they left the dungeon to return to "civilization." The table looks like this:
Roll d%Needless to say, I've never been religious in my use of this table, but I do use it. At least three rival adventuring parties were encountered by the Fortune's Fools PC group (two good-aligned and one evil) and their encounters with these rivals led to some interesting developments in the campaign that my players still talk about. Personally, I love rival adventuring parties and think they're an important part of any megadungeon-centric campaign, which is why I've included several already statted up for use in Dwimmermount, along with the tables I use for quickly generating them.
01-80 No Change
81-90 Evidence of other adventurers (e.g. footprints in the dust, used torches, broken weapons, etc.) is found amidst the room's other contents
91-100 One (1-3) or more (4-6) dead adventurers from a rival party is found in the room. If the room is trapped in any way, the dead adventurers' bodies provide clues as to the nature of the trap(s) therein. If not, their deaths can be attributed to the nearest monsters in other rooms/areas.
101-110 As 91-100, except that any monsters in the room have their numbers reduced by one-half.
111-120 As 81-90, except that any monsters in the room have been slain and their treasure (if any) looted.
121+ A rival adventuring party is currently in the room. If there were any monsters in the room previously, there is a 50% chance that they have been slain and their treasure looted, as in 111-120. Otherwise, the rival party is currently engaging them in combat.