Competition among parents for children's birthday party sites is San Francisco's version of range warfare. Prime spots in Golden Gate Park require advance reservations. Private birthday spots such as the Secret Garden Tea House & Gift Parlour or AcroSports cost more than recession victims can afford. China Beach, a little-used cove tucked below the spiffy Sea Cliff neighborhood, is one of the most beautiful spots in California, and the site of a worn but still-pleasant bathhouse and picnic grounds that provide the perfect site for a party. It got its name because it was a early campground for Chinese fishermen. Just a few hundred yards to the east is the Golden Gate Bridge. To the west is some of California's best surf, so at certain times of year, visitors can expect a steady stream of die-hard wave riders. And the place fills up with a couple dozen sunbathers on afternoon weekends. But for families willing to throw children's parties in the morning, you can typically have the run of the picnic benches, bathrooms, beach, and a view of the Marin Headlands for which nearby homeowners pay millions of dollars.