“ The hammer of a war-god avatar, this massive weapon must be wielded by a giant or other supernaturally strong being. When struck against the ground, a massive seismic wave will propagate outward from the wielder subjecting all in its wake to a massive earthquake. This quake is strong enough to shatter castle walls.”
“ 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.”
“ The two cathedrals in the Citadel stubbornly ring their bells two minutes apart, since each believes the other to be too early or too late respectively. This has been done for over two hundred years.”