For you to have a near-death experience, Death must have a near-YOU experience. Take care to treat him well, and you may be rewarded... eventually.
The PCs are accosted in a major city containing at least one famous fortuneteller / prophet of the future. They are informed that their as-yet-unborn child will (insert terrible evil), and that, although they are very sorry, the PC must be executed to keep this from happening.
A terrible teleportation incident makes inter-demihuman chimaera of all the PCs. Quoth Master Adams: 'I teleported home one night / with Ron and Sid and Meg / Ron stole Meg's heart away / and I got Sidney's leg.'
Telepathically linked twins that have the ability to switch places. Literally. They've learned to exploit this 'tag-team' throughly.
What if some crazy wizard created an artifact that empowered rodents that touched it with one random supernatural power? Preferly right out of the pages of your favorite four-color. (But only one power!) This item does not convey any sort of intelligence boost.
Somewhere along the line, someone very powerful lost their marbles. Literally. Possessing a marble allows incredible clarity of thought about a particular related subject.
The old pantheon is dead, starved to death from lack of worship. If a powerful mortal can create a cycle of Faith, he can become a New God, to some limiting point.
Somehow, someway, a band of gnomes learns how to be ninjas. In fine gnomish style, they open an academy to teach this art to other gnomes. Wacky Hijinks ensue. Or the gnomes become some of the finest assassins in the land. Or both.
While traversing the tractless deserts of Shezmu, the pc's come across a travelling caravan led by Vual, the Demon-Camel, the Lord of Lust, the Thrice-Humped...Vual is cursed to only be able to assume one form outside the Abyss, that of a rather large, golden-skinned three-humped camel,with a frog-like, black, barbed tongue......
Vual is the demonic manifestation of Lust...his followers, a cult of truly disturbed individuals, engage in bizarre orgies, travelling the desert towns, "entertaining" the desert folk with their perverse antics...
Vual's Rapture is what the cultists call their monthly festival, where they perform perverse rites to honor Vual...ofcourse folk come from great distances to witness the festivals, despite themselves, and the Cult of Vual welcomes all...
Surprisingly for such a hideous creature, Vual has the power to beguile and charm with his magical voice. His voice will always sound to pcs as the voice of the person they most desire...his followers also gain this ability slowly over time...
When the pc's meet with Vual, he tries to seduce them into joining his cult. If for whatever reason the pc's resist..well then... Vual would probably kill them for sport, as a lesson for those who "resist Vual's love"....