Don't want to re-live childhood. Old crappy balloon tired single speed with huge wire basket on the front for paper route.
Sailed the seas in my 20s.
Started cycling consistently in my 30s. Still at it.
Bought my first kayak in my 40s. Still at it occasionally.
Took up ski patrolling in my 50s. (think BUSY first aid rooms & ambulance transfer patients)
Became a Forest Service Wilderness Ranger in my 60s. (the backpacking kind of Ranger).
100% retired for good by age 65.
I have found it most satisfying to start a few healthy things you can truly enjoy for life.
Maybe take up grandfathering in my 70s/80s. Only time and my children will tell.