- Guild members must wear lederhosen while on the job. Only Guild members may wear lederhosen. If the PCs are in lederhosen (the Bard's good clothes may qualify), a group of toughs shows up to enforce Guild rules. If the Guild has had the rules written into law, then the toughs have police backup.
- River is running slightly over its banks. And it's raining. The PCs are dragooned into a sandbagging squad - even if they DO have pressing business elsewhere.
- Wearing the color _____ is the prerogative of the nobility / influential family. The PCs show up wearing that color. Snob aristocrat or merchant is not amused.
- One of the PCs is the spitting image of a man who was recently hanged for High Crimes. The locals commit mistaken identity and...
- (Background: the King's writ runs about as far as his bodyguard's bowshot) There's a war on, man, and you walked right into the middle of it. The Duke against the Baron, both are trying to gain alliance with the Mayor.
- The Burgermeister Meisterburger seeks to arrest the mysterious figure who keeps delivering TOYS to the children in their homes at night. (Because breaking and entering, violating Guild privileges, &c) He decides the PCs will make an acceptable substitute, and send a message to the real culprit.
- The PCs are at the wrong table when a bar fight breaks out and the local police "round up the usual suspects".
- A religious schism has rent the city. Members of the minority faith have a temporary and shaky upper hand. The PCs then show up, and any Cleric / Paladin gets suspicious interrogations.
- Previous tyrant has been overthrown, and local anarchists are trying to take long-term advantage of instability.
- "That d--nfool mage built his tower right in the middle of town", and is quietly trying to follow in Saruman's footsteps: invent gunpowder. He may come up with something that really ought to be kept in some farmer's Back 40. Maybe the test batch is more potent than he really thought...
- Urban renewal project has just been enacted, so now ALL the major roads have construction projects blocking them every few blocks. Just try to run away from somebody!
- Thieves Guild has bought out craftsman guilds and is now eliminating all competition, including travelling crofters. (Think: Zhents)
- Cholera or similar plague is brought to town by unassociated others at the same time as the PCs arrive. They might catch it or might get blamed for it.
- Fire in one building causes the building next door (tavern / orphanage) to become unstable. Could you go in anyways and get everybody out?
- River floods overnight, so the PCs wake up to discover they can only leave the inn by boat. Hopefully they did not take a room on the ground floor !
- Flashy rebel (Scarlet Pimpernel / Zorro / Robin Hood) plagues the leader of this city. The Mayor is unable to put a stop to the rebel's antics.