“ A small, primitive village has yet to discover fire, which is a good thing because there are highly flammable (but not otherwise dangerous) gasses in the air. The heroes, blissful in their ignorance, don't know that and think it a wonderful idea to show the locals open flame.”
“ Five men are herding fifteen horses down the road. They won't be very talkative, but are willing to sell a horse, or more horses if the heroes are interested. These men are horse thieves. They are already sought by regional militiamen. Anyone with a stolen horse (all are marked) may get into trouble. If found guilty, horse thieves face prison or even a hanging execution. Similar thefts have happened only a month before, and a reward is offered.”
“ War of the Roses as a campaign plot. Two noble lines converge somehow, each line thinks it has the rightful claim to the throne. Deciding this long ago was handled by some divine intervention, requiring both houses to come together at some point. They aren't so willing to get together this time. Civil war, or a new king?”