I get adventure ideas from weird places.
Werewolves of London: A famous British punk/metal/dance/whatever band is touring the PCs' city. They're lycanthropes, and when the full moon is out their hotel room isn't the only thing getting ripped apart.
Roland the Headless Thompson Gunner: Roland Tembo was a Norwegian merc who died in Africa in the 60s, murdered by his fellow CIA mercenaries. He's haunted violent conflict ever since and now he's stalking the periphery of whatever big fights might be brewing in your PCs' hometown, or maybe he's bringing chaos with him, upsetting whatever fragile status quo might be in place. Roland could work as a demonic spirit, a powerful ghost, or even something like a Dullahan (headless horseman).