Strolen's Citadel is an actual place of learning in the world- what is it like?
A fey spirit masks itself as a bee which investigates all who travel within a specific section of the forest. Any the bee finds worthy are allowed to see the hidden opening into the fey kingdom, just off of the trail. Any deemed unworthy see only the bee, buzzing around around them momentarily before moving on.
A common mistake when writing adventures set in deserts is to assume that the climate is too ferociously hot to wear armor. Historically, most battles in deserts involved troops dressed in protective armor. Although they would have been miserable during the hottest part of the day or the hottest part of the year, desert weather isn't intolerably hot 24/7.
A small band of squirrels seems to be fighting high up in a tree over a shiny nut-sized object. Can you retrieve the prize without scaring the squirrels into running off with it? If they do, can you manage to chase them down?
God has been slayed by a mortal man and his head is now worshipped and put on a pedestal. The PCs are hired to steal the head and bring it to a mystic that claims to have the power to revive God.
When the campfires grow dim, stories are told. Stories of lost cities, great heroes and legends of old. One of these is the story of Knurlheim. Once the proud capital of the Dwarfs, now a ruin- abandoned long ago. Filled with vast riches and treasure. It’s secrets forgotten with the decline of the Dwarfs, long ago. No one knows is certain if it ever exsisted at all.
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.
The PCs find a small green glass bottle, something can be seen writhing within the smoked glass. If the PCs open the bottle a repulsing form of life will pour forth and grow in size. A genderless beings of soft pliable purple flesh towers before the PCs, it has no detail, no distinguishing characteristics except for a narrow slit for a mouth that holds rows of inwardly curving teeth.
The babies of a small village has been disappearing lately, rumour has it that a demon living in the forest has taken them. The monster has the appearance of a shriveled old woman. A hag, disheveled, with maniacal appearance, wild-looking hair, and an oversized gaping mouth. Long pendelous breasts. The villagers say she eats the newborns and has sharp claws that are created for mangling. No one dears to challenge her, enter the PCs.
During a storm the PCs come upon a little boy that plays in the rain. Upon further inspection they discover that he has one eye and a long tongue lolling in its mouth. Spit dripping. It is a demon from beyond that can access our realm during storms, it eats all heads that are not its own, living and dead.
Moonlight shines down on the tranquil scene of a slumbering inn along one of the many roads that cross the land. Trees sway gently in the night air, and the stars twinkle brightly. All is quiet as the PCs snore away, a fine tendril of smoke curlsrnunder their door. The tavern is on fire! This is particularly bad news if the PCs own any horses - the screaming they hear is probably from their mounts! Panicky people are rushing about with buckets of water, trying to tame the flames. The fire fighting effort is not very coordinated as everybody is either hungover or still drunk, including the PCs. Hurry!
While traveling trough farm land the PCs come upon a merchant sitting on a wrecked wagon without a mule attached to it, hid face burrowed in his hands. He explains that he was robbed by petty goblins, unable to defend himself he had retreated. He asks the PCs to help him retrieve the mule before the goblins roast it, as a reward they may keep his goods. How hard can it be?
Whilst exploring underground the PCs discover tube like tunnels stretching for miles, upon further inspection the strange tunnels seem to connect all major cities in the are, what is their purpose?
A floating city hovers over the capital, seemingly appearing out of nowhere. Its spires are blinking in the morning sun, revealing alien architecture. What will happen next? Rumours spread like wildfire that this is the ancient city that once stood at this very spot. Mystics proclaim that it will take root here once again, crushing the capital under it. Somebody needs to get up there and investigate.
A legend tells of a people living deep in the desert, they appear at first as ordinary human beings, sometimes impersonating someone familiar to the PCs, before causing their features to disappear, leaving a blank, smooth sheet of skin where their face should be.
In the harbour of a major city a large and terrifying ship made of human nails docks. Nobody seems to inhabit this ominous vessel, someone needs to go on board and unveil the mystery. In comes the PCs.
The road has never been more than an overgrown mud track, little travelled and little cared for, petered out to nothing more than a flattened earthen line, barely distinguishable from the rest of the landscape. The soil is dark and fecund and dark oaks stand like sentinels at the forest edge, their branches high and leafy. From them hang grizzly human bones, skulls and shiny precious stones. Who put these strange totems there? Are they warnings? Do the PCs dare to take the stones?
A circus is in town and while parading down the main street the animals suddenly break free from the cages. After surviving and assisting during the breakout the PCs are hired to help with the investigation. Who did this and why?
The PCs find a strange helmet, when donned it will take control of that PC and speak and act trough him/her. It explains that it is benevolent and needs their help in a quest and that it will stop possessing the PC when the task is done. Great if a player is gone for a number of sessions.
All magic is suddenly gone. No mage can sling sorcery anymore. This upsets all empires and civilizations. It is soon discovered though, trough the combined work of mystics, scholars and dreams, that all the magic has been drawn into a single orb in a vast tower located at one of the poles. Whoever gets there first wins the greatest price in history, access to all the magic in the world. But who owns the tower?
When running a new party, get around the question of plot density by having the first discovery to be a deck of fate, or whatever you call it. If you use a real deck, you should definitely stack it to have the desired outcome, which is to curse the party to attract weird things to happen and involve them. This should not be told to the players at the time, so that they won't just up and try to get themselves 'decursed'. Though quite why they would want to is beyond me.