Yoga is a much easier way to exercise both mind and body than testing Einstein's theory of relativity by racing a beam of light. Avoid a science-related sprain with today's Groupon: for $39, you get two months of unlimited Bikram yoga at Detroit Bikram (up to a $300 value). Choose between two locations: Troy or Farmington Hills.

At Detroit Bikram, yogis warm their muscles, joints, and sinews to achieve maximum malleability while bending in studios heated to 105 degrees. During the 90-minute classes, students capable of twisting themselves into any letter—whether it be a lowercase "i" or the Chinese character for "meatloaf"—stretch, pose, and breathe their way toward goals such as heightened energy. For two months, students can pick from a packed schedule of classes and—after their initial visit—can visit either location for heated Bikram yoga classes. A stable of 12 instructors leads students through each stretching and breathing exercise. View preparation tips to maximize the benefits of each sweltering session, which may include weight loss, detoxification, and achieving a state of bodily purity akin to dechocolated chocolate milk.