Yay, I’m a big fan of city games 
we dabbled in it ourselves in our city of Ghent a few years ago with a cat-and-mouse style Vampire Hunting city game.
There is another session that we’re planning to be somewhere in the city: @albertorey 's fly fishing demo. Is there a way to make that part of the city game? Eg.
We were also hoping to do some DIY water quality analysis during that session. I think there’s plenty of potential to do small citizen science projects during the game . Anything that produces data, basically: air quality, quantity and type of trash on the ground, dangerous obstacles for bikes, spotting bird nests, collecting urban fossils. Pinging @rachel as well.
Not sure if the tempo of the two activities would clash or not. City games are hectic in my experience, while I envision the fly fishing as a relaxation moment.