- bike/walk/run every street in your city. Can use for instance https://wandrer.earth/ with Strava to track it. It's quite nice, discover all kinds of things in my own neighborhood I didn't know of. By habit you always take the same routes. This makes me take a new road on my way back home and see new stuff.
- Draw art on the maps using gps. I've done multiple. Takes planning and often a few attempts executing when you realize that road is closed, that path was flooded or whatever. I've even gotten in the news a few times from this. For instance when I ran this pest doctor during lock downs https://imgur.com/a/qRkB5QN
- Bike the longest distance using the smallest area. Basically find a roundabout and see how long you can take it. Or the opposite, the largest area in your city, basically bike its border.