Given the hoo-ha over supposed "mature content" in Monte's secret project, I might as well mention the following. This was some years ago.
The PCs were hired to find the lost children of the local baron: a couple of kiddies, a boy aged 10 and his sister aged 8 (or thereabouts). The PCs were just 1st level, so not much worry about divinations spoiling the show.
Most of the first half of the adventure was pretty wacky. For example, they met an old half-crazed guy in the village, who had a mushroom patch. When he ate his mushrooms, and I quote, "I can see things!" Eventually, they pieced all the the clues together, half of them from the old man, courtesy of his mushrooms. The kiddies had been swiped from their room by some fairies in the middle of the night.
So, the party tracked the fairies down to their hidey-hole in the forest. There, they met the children, who were quite safe and sound. This was pretty much as the players had been expecting things to turn out. They were not, however, expecting the kids not to want to go back. This was because their father, the baron, had been molesting them for a number of years; first the son, and then the daughter. The tone of the session took a 180-degree turn at this point. When the 8-year-old described her daddy doing "bad things" to her, you could have heard a pin drop.
To cut a long story short, instead of returning to the castle, they skipped town and took the kids with them. Eventually, they learned that the hapless baron had come off second-best in a fight with a lich, got possessed by a demon as punishment, and been forced to do these horrible things. He learned first-hand that there are many ways to break a man.
Why did I pick that topic? Because it was in the news at the time, with a Royal Commission into pedophilia uncovering all sorts of icky stuff daily (a bit like the scandal going on with the Catholic church in the US at the moment, I think). Also because I wanted to have something that the players could react to at an instinctive, emotional level.
No, it was NOT very appropriate for a D&D game, possibly a cheap trick, and looking back, I was definitely taking a huge risk. If I were to run that session again, I'd pick something safer. But it worked out okay in the end, the players were cool, and that scene with the players all dumbstruck remains one of the most memorable moments in my time as a gamer.
Hong "hey, where's everyone going?" Ooi