“ 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.”
“ It looks like a cook's book. It is a cook's book. It is also where the cook, who happened to be a master spy, encoded all his secrets and contacts. The book has innocently fallen into your group's hands. Everyone wants it, and many are not subtle or peaceful in their attempts.”
“ In a long-lost age, a party of adventurers are frozen into stone by the stare of some gorgon-like creature. An unscrupulous rogue, coming across the frozen party several centuries later, decides to haul off two of the statues to decorate his den. Upon his death, an artisan friend of his claims a statue and sells it to a rich merchant, passing it off as his own work. Years later, the merchant gilds the statue in bronze and re-sells it at a much higher price. After passing through the art markets for many decades, the statue ends up in the hallways of a mage academy. Imagine the chaos and confusion when a young mage's spell happens to break the curse of stone, returning the adventurer to life several centuries after his petrification! Is he interrogated by historians? Driven mad by the change of times? Or does he set off on a quest to find and liberate his other frozen party-members?”