Instead of Hatha Yoga (180 calories)...
Try Hiking Yoga (400–610 calories)
Sneaker-clad certified yogis will guide you briskly through parks and along trails, pausing to lead you through basic yoga poses. In a win-win-win workout, Hiking Yoga; gives you cardio and toning benefits of hiking, the mind-body treats of yoga, and the brain-and-mood-boosting effects of spending time outdoors. And when the instructor tells you to feel the earth beneath your feet or turn your face to the sun, you'll be able to do exactly that. (Drop-ins $20; yoga hikes take place in 14 cities so far—find one near you.
Calorie counts are based on a 150-pound woman working out for 60 minutes, using data from the book Exercise Testing and Prescription, by David Nieman.