Somewhere along the line, someone very powerful lost their marbles. Literally. Possessing a marble allows incredible clarity of thought about a particular related subject.
“ In this dungeon, the monsters will not be hostile unless you take something without permission. If you do take something, the monsters inside will consider it stealing and attack you.”
“ A town has a festival every year in the dead of winter. The festival of birds. The towns folk dress in feathery robes and beaked masks and dance and frolic in the belief that the changes of the seasons are controlled by the presence of birds. According to tradition, the festival tricks Spring into coming early because the birds have returned.”
“ The PCs are sent with a diplomat to another country to protect him and do his bidding. There may be some espionage, rescuing, downright bullying, etc. Could make a nice medieval, special operations background.”