There is an important pair of fraternal twins. Possibly minor dieties, sorcerers, or maybe just an important pair of nobles. One is evil and one is good. The thing is, the one who looks evil at first glance is the good one, and vice versa.
There is a person who has a well-known reputation, probably involving something illegal. But this person is either very clever and crafty, or really like his or her privacy, for no one knows who this person actually is. As an added twist, perhaps this person is of an age that would noramlly be wildly inappropriate (say, a child is a much-feared bandit) or maybe not the expected gender or even race.
One of the most wanted assassins in the realm looks exactly like an important person (local nobility, PC, etc.) This may or may not be common knowledge.
There are those as rich as kings but dress as peasants and worry not about funding. To visit their true homes one would see wealth of untold value scattered as dirt is in a hut. They know the monetary value of their possessions but they have long lost any true value to their owners. Experience is their currency and their curse. They dispense secrets of the ages as if discussing the weather. Few things have they not experienced so that very little gives them joy. They are the lost ones looking for new life while humoring the mortals around them.
There are reports of a monster that lurks in the tops of trees and drops down on unsuspecting people. It causes them no damage but it frightens them with a hide-like face with big dead eyes, drooling and barking like a dog while unsuccessfully attempting to have intercourse. The PCs investigate and find that it is the local village moron that is doing the spelunking in the woods. How can they explain this otherwise pleasant and merry man that it is wrong to put on a mask, drop down from trees and attempt intercourse with relatives and neighbours.