I love little towns with a lot of mystery. I love weird, freaky cults and weird, freaky goings on. And I love material that I can use in any setting, especially my own.
So I snatched up Moon's Folly in a hurry.
So take a town, plant it near a pre-historic megalithic structure. Fill it full of humans, elves, fey and lycanthropes and all peacefully worshiping the Moon Goddess, add your PCs and I am sure something is going to happen. But in case you are at a loss for ideas, there are plenty in this book. Did I mention that there some lumberers wanting to cut down the forest for profit? Yeah they are there too.
Reminds me a bit of the Village of Hommlet, if Hommlet was in the Scottish Highlands surrounded by dryads.
There are plenty of other secrets and plenty of NPCs to keep a Game Master occupied.
The one thing it is missing though is some sort of threat the Characters can solve the old-fashioned way, with sense violence. Not a requirement mind you, but players do enjoy a good combat session. The Keep had the Caves of Chaos, Hommlet had the Temple of Elemental Evil and Moon's Folly could do with something similar.
All in all, an enjoyable work and a great starting place for a group of new adventurers.
[4 of 5 Stars!]