1. Van Halen Backyard Ultra

Van Halen Backyard Ultra is a small backyard-ultra race, capped at 20 runners and run under the classic last-person-standing format. The basic rhythm is simple: everyone starts a 6.706-kilometer loop together, and the next loop starts exactly 60 minutes after the previous one began. The race can run for up to 48 hours. A runner must be back and ready for the next start on time, because missing the hourly start means a DNF. Each loop has to be finished inside the hour, including the final one, and runners cannot receive outside help during a loop or use aids such as poles. The winner is the runner who completes one final loop alone; everyone else, even those who ran for many hours, is listed as DNF.