One of the things I enjoy is brainstorming campaigns. Here's a few of my favorites, feel free to add your own to the thread.
The Goode Folke
Long ago in the Hills of Southern Britan a battle was fought between our world and another. A malevolant force haunted a nearby dense and twisted forest. When children and livestock began to vanish the woods were searched by the menfolk. At it's center a cirlcle of obelisks, shaped from still living wood. The center was littered with the bodies of the missing children.
The men took up fire and axes to the foul things. However they found the threat was not physical, but a mental one. Of the thirty men that entered, a mere 12 emerged from the ordeal sane. Emboldened by the prescence of the villiage priest they destroyed the foul monuments. What ever force that inhabited the forest was banished back to the netherworld It crawled from.
It has been over 1,000 years. The Force has re-entered our world, hungry for blood and revenge. It's instrument is a young priest, a descendant of the village priest that thwarted It's hunger. First the It warped his body, then broke his mind. The wretched Fomorian travels the land reactivating places of power long dead. It hunts the decendants of the 29 men that accompanied it. It is their blood That will free it's master.