Including more than one story is important in any ongoing campaign. I’ve written before about how players want a break from the overarching story, and need to be given the chance to see how big and deep the setting really is. I recommended breaking up the usual missions that forward the overall plot with smaller side quests that are simply fun to explore and play out. I have had to balance this though, and make sure that I’m not constantly throwing adventure hooks so frequently, or in so many places, that it becomes a mystery as to how any non-adventurers survive in this world. It might be tempting to just have wizards teleport out of nowhere, or have rampaging dire wolves charge into the tavern, but you have to think about where things happen, and what the implications are.
Taverns are a great place to have adventures start, but remember that this is supposed to be a public place with frequent patrons. It’s a business, and it is in town. Usually if trouble goes down here, I like to have the bartender react in one of two ways; either they are totally prepared and jump into action with readied courses of action, or they are terrified and have never had to deal with it. When one of my players had an assassination attempt made against him in the night, he complained to the innkeeper the next day. The innkeeper was horrified and promised to “improve security”, though nothing like this had happened before. After the third assassination attempt, the innkeeper decided to sell the place and leave the innkeeping business all together. However, another bartender might have protocols in place when the local barbarian comes to drink; all breakables are locked away, tables are pushed aside to make room, and a wand of baleful polymorph is put on display as a reminder not to start trouble.
The market of a city is another great place to start random adventure hooks. With so many people from so many places, there are lots of excuses to include interesting side quests. I recently had the party investigate an “abandoned” building beside the market, only to discover it was the location of a smuggler’s guild. On more than one occasion I have had a shipment of exotic and dangerous creatures break free in the market to cause havoc. Sudden duels between angry wizards, the discovery of an artifact among antiques, and civil protests or unrest are all feasible adventure hooks in a busy market. Remember though, this place is supposed to be where people are constantly doing business, so it doesn’t make sense that every market you go to will have something exciting happen. This is a place with lots of normal, non-magical people and their safety is paramount here, so there should be guards or other protections. Don’t make every market a fascinating place, because some are just really great places to shop and enjoy lunch.
Out on the road, the classic locations of “random encounters”, is a prime location to have weird stuff happen. One of my big challenges however, has been making sure I don’t drag out a campaign by making every single trip some kind of adventure. The party leaves town only to come across a crater in the ground half an hour away with a strange device inside. The next day they come upon some small cottages that are not on the map which turn out to be people-eating monsters. The next day they happen upon a minotaur claiming to be lost and asking for their help. On the last day of their travels, a young white dragon swoops down, spraying his icy breath weapon on them, and stealing their mule before moving on. How does anyone survive the roads in this world?! I have taken to describing that journeys between cities take much longer, and only give one or two encounters set in that time. Sometimes there will be no encounters, and I treat the travel time as downtime, saying that they reach small towns and settlements along the way, even if we don’t roleplay it. It makes a lot more sense to say that in a 2 week trip, the party encountered a couple unusual things. Maybe they were investigating something off the road that most travellers would avoid, or whatever, just make sure you don’t inadvertently make the most dangerous place in your world, the open roads between cities (unless that’s a major feature of your setting of course).