Some things I play around with for fun from time to time:

I am making some maps

First up: A map of the 10mi radius around the MBTA (bus+subway+CommuterRail), as I evaluated a decision to buy a folding bike I could bring on transit:

Next: Investigating how to get from Boston to NYC by stringing together 5 public transit systems

I maintain a personal DeFi wallet

I love being able to manage all my assets, in all my protocols, in one app. Existing solutions don't work smoothly enough for me, or don't cover all my needs, so something bespoke has been really nice to have. Let me know if you'd like access, but I make no promises about proper functionality or whether it fits your needs - I just hack on this for my own needs whenever I have the urge!