“ The blood of a dragon is vital in the creation of potions of longevity. The liver could used to cure any disease or ailment, while the heart could restore a PC to full and complete health, despite their age, or injury.”
“ 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.”