Everyone can think of a favorite song or two (or three) which can easily be translated into a fantasy rpg concept, be it an item, plot, location, or what have you. Just take the lyrics of your favorite real-life ditty, and go from there!
This is a scroll for every rumor or tale you might here from a friend or in a bar.
The characters are unwittingly embroiled in a rebel organisation, and must lead the Black Shield fighters to victory against the evil Halar, seeking out new hideouts, rescuing people from towns and generally doing what Robin Hood would have done in their situation.
A casual remark by one of the party about something met on a previous adventure leads to a summons to and grilling by the Mages' Guild (or equivalent), probably resulting in an expedition back to that area to recover the things for 'study' by the Guild. The party's presence will be 'requested' for this expedition.