Take two willing kids who love each other and weigh about the same (within five pounds, anyway)! Find a sandy spot. Explain the rules: no kicking, punching, biting, hair pulling. Play begins after each successful "pin" (both shoulders of opponent held to the ground).
Liberal amounts of laughter, audience cheering and gasps, and hugs between rounds are highly recommended.
Sand wrestling! This went on for a lot of our camping trip earlier this month, drawing stares and gasps from passersby (and from their mothers, too)...these two cousins were well-matched. We expect that in a couple of years it will be the younger of the two who is mashing his cousin's face into the sand. For now, she has the upper hand. And he loved every minute of it.