“ A man has been committed to an asylum for schizophrenia. The doctors are convinced that he is suffering from delusions and hallucinations. The reality: His soul has been split among three bodies, each in a different dimension, and he occasionally feels and sees what his other 'selves' do.”
“ What if the sources of precious metal in the realm all failed, so that the only sources for gold and other precious metal were hostile foreign lands? Gold coinage might become increasingly rare, resulting in hoarding. Player characters that appear with masses of treasure might be suspected of being in the pay of foreign powers.”
“ 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.”