#ShowerThoughts, how about an RP centered around the events in other parts of the city while a city/region/global event is occurring.
In one of my storylines, my main, Galrithius, gains the ability to enact Convergence, basically the zombie apocalypse, with icicle shooting, darkness spewing, and fire breathing zombies, undead knights, massive bone beasts, and all kinds of fun horrors. But, the events central to that are so specific.
Think of it like the stories surrounding Hurricane Atlas, a family being saved here and a villain trying to take advantage there. There could be a number of vignettes or a cohesive sidestory taking place outside the red-skied Halloween event ;)
Wanna give it a try? Hopefully it can be interesting enough but also not overly reliant on the Convergence storyline.
Backstory link: https://cityoftitans.com/comment/165389#comment-165389