Depends on child's age, but here are some things from today that I would have probably found endlessly entertaining when I was a kid: Flipper Zero Raspberry P

Depends on child's age, but here are some things from today that I would have probably found endlessly entertaining when I was a kid: Flipper Zero Raspberry PI SDR Not a computer, but still very relevant for inquisitive kids and adults: Amateur radio (an oldie but a goodie) Decent telescope Decent microscope