It's not even close to Halloween, but good ghost encounters should take place when no-one is expecting it, as clichés are only entertaining when repeated endlessly, and then only for a bit...
THIS - a Ravenloft Netbook of Haunted Sites, inspired by Ms Brown's work, dating from 1999. I remember that sourcing anything called a 'netbook' contained it's own dangers, usually quality, but this looks just like it says on the tin, and it's only 300 kb pdf.
Anyway, based on the 101 hauntings, and various other thoughts, I've developed 9 that work for me in a low fantasy setting. The correct way of 'solving' these hauntings is up to the GM - killing the ghost with a special weapon is one way, but I prefer the TV drama approach of work out what caused it, set it right, and watch the ghost wave you goodbye. Or die a truly horrible, final death. Depends what you want to achieve out of the encounter - Grimdark or My Little Pony?
1. A lake or river where suspected witches/mages/psychic talents were thrown - the guilty ones survived and were killed in more entertaining ways. Some nights (every, some, full moon, etc), drowned corpses grab passing boats and attempt to climb in. The sailors are not keen on this.
Solve by - getting a corpse to shore; knocking down something of the witch-drowners; going underwater to see what's there.
2. Derelict shipwreck on a deserted point. On nights of the full moon(s), the ship appears whole, with lights and the sounds of ... a party?
Solve by - entering the undead infested wreck and putting the captain's ghost to rest; finally deliver the cargo in the hold to it's owner; enter the ghost ship and prevent the events that led to the wreck.
3. A noble spirit (of light and goodness) haunts the graveyard since tomb robbers stole their jewellery/ family heirloom/enchanted sword. This hauntings is upsetting good honest folk.
Solve by - regaining the object in question; convincing the undead haunting that material goods don't matter; discovering why their descendant stole the goods and framed an innocent bugler.
Solve by - leading the spirits Piper of Hamelin-like to the Cave to the Lands of the Dead; harvesting the magical power of the balls for a wizard that pays well; perform a ritual when the moons align.
5. Those riding past the deserted cemetery at night often feel one or more people on the back of their horse, but no-one can be seen. Sometimes it freaks the horse out, and it runs all night, expiring at first light, miles from anywhere. Other times, no effect other than terrifying the rider.
Solve by - finding out what tragedy occurred in the cemetery and resolving it; delivering the passenger to a ruined, equally isolated place of safety before first light; entering the cemetery at midnight to confront and banish the wraith.
6. A workman killed during the building or demolition of a building returns as a ghost each night, endlessly repeating the activities of that day, which is scary when the structure doesn't exist any more.
Solve by - retrieving the man's bones from the rubble pile they were cast into; uncovering historical financial misdeeds that led to the death (cheap materials, no safety, dangerous practises); gaining special (magical, spiritual,historical) tokens to safeguard the haunted structure.
7. A person drowned in a communal well. Now, a dripping bedraggled figure climbs out of the well on foggy nights, and heads to one particular nearby room, which is always damp and cold. Scares the daylights out of anyone in the room when it happens.
Solve by - descending into the strange dungeon at the base of the well to recover the body of the drowned; stay in the room for an entire night of haunting, breaking the curse; convince local authorities to fill in the well.
8. A thief killed, falling from a sheer wall. Now every night footsteps creep through the corridors of the building in question, as she tries to complete her mission.
Solve by - completing the mission and delivering the hidden note/gem/bone in the secret location to the thief's master (even if the master is now (un)dead); convincing the Thieves Guild to call off the mission, 50 years later; carving footholds in the wall so the spirit can escape.
9. The bell-ringer (hunchbacked or not, your choice) at a Temple falls from the belfry and is killed. Now all the bells sound on the anniversary of this death, with no-one near the bells.
Solve by - discovering which of the bells is cursed and removing it; uncovering the conspiracy at the Temple, or amongst the Bell-ringers Guild; convincing the Temple's head priest to rebury the bell-ringers bones in the Temple grounds.