Bay seniors whose love of tennis is stronger than their knee replacements have public courts all over the area to play on. Near the top of the list of loveliest sites are the ones in Golden Gate Park. Surrounded by lush landscaping that cuts down on winds wreaking havoc with your returns, the 21 courts are located near Nancy Pelosi Drive (who knew?) and are bargains for seniors -$3 on weekdays, $5 on weekends. Open from 9am to 4pm. Playing time 1.5 hours. Instruction available. For matchless views of the City and the Bay check out the four Alice Marble Courts on Russian Hill. No fees apparently.