“ 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.”
“ You pass through a woodland with a floor that seems remarkably clean of debris. Suddenly your attention is drawn to a twisted bit of wood by the trail side, a short broken twig with several stubs of branches along its length and most of the bark missing. When you reach it, the twig blurs and turns into a small brown lizard, caught in the middle of its body-twisting run. The little reptile darts away down the trail with impossible speed, no doubt magically enhanced, and is lost to sight in a moment. Now someone knows you are coming...”