“ 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.”
“ The PC's end up in a strange world where the very rocks are made of gold and jewels.As such gold and jewels is worth very little, but the iron in their swords and belt buckles is suddenly worth a LOT.”
“ At regular intervals, a god takes control of your world's weather. Choose the gods at random each turn of the interval and begin applying their effects subtly. Their power will depend on the strength of those who worship them.
For civilised people, worship of a god actually wanes during that god's month in an effort to reduce their potential destructive effect.”