Though many members of college orchestras spend the summer months at their parents' homes or bicycling through Europe, enough young musicians live in the Bay Area to cobble together a respectable orchestra. This is the premise behind the UC Berkeley Summer Symphony, a collection of fine musicians from the region's many youth orchestras. It doesn't have many competitors right now, and its performances this weekend are free. So, if you're looking for a little Shostakovich to balance out your days at the beach, this is the place to go. The program includes Shostakovich's Fifth Symphony, Dvorak's "New World" Symphony, and Rimsky-Korsakov's Capriccio Espagnol.