“ 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.”
“ A ghost is haunting someone with a secret-it\'s not that he murdered the person that became a ghost, it\'s that he went into hiding with a new identity to avoid being murdered, whilst the ghost wants him to join her in the afterlife. The ghost is getting stronger and more dangerous each day. Enter the PCs.”