I nominate flyfishing as the perfect sport for geezers. It’s cheap, physically undemanding and serenely solitary. You can start off your new hobby without leaving the Bay Area, if you don’t mind not catching any actual fish. The flycasting pool in Golden Gate Park, built in 1938, is rich in fishing lore and it offers free casting lessons the 2nd Saturday of every month. Across the Bay the Oakland Casting Club in McCreaPark off Highway 13 also provides instructions for beginners for nothing.