Not to be one of those people who talks about the weather, but has this summer's concert-going season seemed sorta... washed out to you? Multi-day festivals from Lollapalooza to Catalpa to Pitchfork have been plagued by rain delays, and other outdoor concerts have been similarly doused. Shows at the Nikon at Jones Beach Theater, which is right on the South Shore of Long Island and surrounded by the Atlantic Ocean, are rain or shine, though, so last night's Deftones/System of a Down show went on despite a pounding rainstorm that turned part of the venue's plaza into a pond and made plastic ponchos the merch booth's hottest commodity. The Deftones, who went on first, gave a master class in keeping a soaked crowd as happy as they would be on a starry 75-degree night. A few lessons from last night that any band thinking about playing an outdoor show should learn.