I can’t believe this is the TR forum
Definitly Rocker Plates for Trainers should have referenced in this thread. Craft for bikes!
oh. building and maintaining fishtank(s) is also fun thing to do. Get the substrate, make filtration system, put right amount of light for aquatic plants, place beautiful fishes, etc. Once you bring all things to right place, just looking at it will eat lots of your time.
If you plan to have kids, those free time will then be your distant memory of joy… Hope you enjoy your free time 