I have recently started a Play-by-Post campaign in my megadungeon, Monster Hill. As per the concept of Monster Hill, anything these players do will carryover to every time I play. So if I'm still running Monster Hill ten or twenty years in the future, I might offhandedly remark "Hey, that's the corpse of one of the first Player Characters that delved into this dungeon!"
A few interesting PCs include Zaggle'Bo, the goblin cave druid and Onnam the Guide wood elf cleric of Hades (I have decided to use real world deities for the humans in this campaign). They seem to be developing goals that might just have a strong impact on the course of the campaign. This is, to remove the corruption of Monster Hill. Ironically, this corruption comes largely from portals to Hell, Hades and the Abyss. Hades of course, lives on the plane of Hades, albeit on Pluton not Oinos to which the portal leads.
They are soon due to encounter some bandits. They have already encountered an orcish slave of the bandits in a cave which serves as a stable for the bandits. The pool in this cave is sometimes inhabited by faeries with powers of healing, a reference to the Legend of Zelda series.