Joe Hendricks, a former pro BMX biker who once made a living doing half time shows at sporting events and even starred in commercials, Is now leading the world's largest and free boot camp. Workouts are often held at Red Rocks Park but make sure to check online (itburnsjoefitness.com) for the current location. Classes have reached up to 300 people and are open to all fitness levels as modifications are offered. Expect intense cardio- with stair and bleacher running, ab and core strengthening, plyometrics, military exercises and yoga. Some of the most fun parts of class are partner exercises where you may find yourself piggybacking a newfound friend or trying other exercises you haven't found before.