Feeling indoorsy? Table tennis is just as competitive as the full-court version and inspires hundreds of tournaments held all over the globe. In North Beach, players 5- to 75-years-old practice at AMDT Table Tennis Training Center (1968 Powell St. at Lombard), which offers coaching Monday–Friday. The SF Table Tennis Club plays open-challenge games on five tables Monday and Friday 7:30–11 p.m. and on Saturday 1:30–5 p.m at the Potrero Hill Neighborhood House (953 DeHaro St. at Southern Heights). Don’t be surprised if you get crushed by someone your grandfather’s age.