Three I had while  walking around making maps with Leo today:

1. Take all of my runs and plot them as a SVG. Map the streets of the the world by running.
2. It be neat to have a custom map logging local vending machines and their cashless status.
3. It would also be neat to build a map “from scratch”. Walk / ride streets to build the lines. Maybe denote portions in different colors to reflect terrain. What would it be like to not have mapping data and have to make your own personal maps?