With regard to the plot "Sleeping Mines of Elathon":
You manage to get the water wheel in the mine working which operates a pump to clear the flooded lower levels. As you explore the dank tunnels of the lower galleries, you can hear the creaking of the wheel above. You enter a low-ceilinged passage and are crawling on your backs, when the creaking stops. The water starts seeping wetly around the back of your head...
The PCs come across a town with a strange curse: Every morning, those who have grown up here wake up with the memories of someone else. They do not find this strange and have no idea it is happening. They calmly wake up and start these new lives as though they have always been that way.
The cause: A wizard who lived there was spurned by a maiden he was infatuated with. His attempt to manipulate her memories into believing they were already together and that she loved him went horribly awry.