Bay Area seniors who don’t think of the Fairmont Hotel neighborhood as a transcendent spiritual center may have their minds changed every Tuesday night in front of Grace Cathedral. There from 6:30 to 7:30 yoga sessions take place on the floor labyrinth just outside the eastern doors. Geared towards beginners as well as more advanced practitioners. Bring a yoga mat. Pay by donation. It’s much quieter up there now that the California St. cable car line is closed for repairs.