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...
In a small, genetically isolated region it is not uncommon for the locals to have three arms. The third arm is generally a second right arm that is a good bit weaker than a normal arm and is generally held against the chest. This hird arm is most often used to carry small things, though some of the more skilled craftsmen have learned little tricks with their third arm.