The blackboard of the middle ages
A large steel shield in the form of a sea-shell attributed to Athena, the goddess of civilization, craft wisdom and war.
A Castle or better a fortified tower is floating over the country side and being attacked by goblins (or other monsters, depending on PC strength)
PCs camp for the night in a dry pine forest. Fire skill of the person that made it is usually pretty good, but during the first watch the unexpected happens: a spark lights the surrounding woods and a brush fire quickly starts. Be quick or it could turn into a disaster that could affect the entire region.