Split the teens into small groups. Give each group a flip flop and a list of clues. Each clue leads to a specific item. Once the team finds that item they measure it with the flip flop. For example here’s a clue I used at camp. “If we’re making s’mores we’re probably sitting around this…” They groups would be led to the campfire and measure the fire pit area (make sure it’s cooled off!). The first group back with the answers and flop measurements win!