The Marines of Camp Pendleton host this day of stand-up and prone paddleboard races, outrigger canoe and surf-ski races, a one-mile open-harbor swim with separate races for adults and kids, and a vendor village. The event is highlighted by the Elite Amphibious Assault with soft-sand running, cargo-net scaling, inflatable-slide jumping, and a grueling stand-up paddleboard race said by many premier athletes to be the most physically demanding event of the year. Open to Marines and civilians alike, with events for all skill levels ages nine and up. At Del Mar Beach at Camp Pendleton.