Sometimes we need the added pressure of a financial investment to force a good workout. The threat of public humiliation doesn't hurt, either, and boot camp just sounds cooler than aerobics class. At Genesis, the pain doesn't come cheap, but the instructors are experts at kicking your butt. The POWER Boot Camp is four weeks of daily (you get your weekends off at least) heart-pumping, muscle throbbing hour-long circuit workouts. No two days are ever alike, as the instructors rotate. Our personal favorite is the classic-rock-loving Iraq veteran Jon, who refuses to open the door or turn on a fan during class, as if fresh air had calories. Walk into his gym and you're likely to embark on the impossibly tough "1200." That's 400 sit-ups, 400 squats and 400 push-ups divided into 20 sets of 20. Miss a class and you'll start the next one with 25 push-ups. Sound easy? How about running suicides after you've run up the hill at Riverfront Park holding a medicine ball over your head? Or sprinting uphill on a treadmill without tripping and flying off the back? Jillian Michaels has got nothing on these guys.