Kayaking is nearly free weekend activity, once you have (or borrow) a kayak and oars you’re good to go! Bring a sandwich and tap water in a recycled water-bottle for a nearly cost-free enjoyable experience like the one I just had with my daughter, relaxing along a quiet river in nearby NH. Was SOO excellent to get away from computers and the house-needs and the city! Thanks!
and PS I realize it’s not 100% free as there were automotive 60c per-mile to drive to the river area but I combined it with a family visit, and yes someone had to buy the kayak (it was a gift), but only once… after that the trip-to-trip cost is extremely low, and the Kayak just gets hosed off and stored in the garage where it doesn’t take up room as I have a homemade suspension from the roof. Zero consumables like gasoline, oil, nor regular maintenance like a jetski, so mmm would be proud. There is a net health BENEFIT of it requiring physical activity, too, and that’s important in retirement or acting-like-retirement.