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 $45, you get 10 yoga classes at Mindful Turtle Yoga and Wellness in Stony Brook (a $130 value).

Led by a team of dedicated and dexterous teachers, Mindful Turtle Yoga and Wellness offers an extensive schedule that helps students of all levels to meld their mental, physical, emotional, and spiritual strength into one balanced body. Hatha yoga classes build a foundation for the patient practice, teaching yogis the basics of form, alignment, and breath, and multilevel flow sessions demystify the secrets of saluting the sun and memorizing all of Jupiter’s moons. Breath-synchronized movements course through a series of postures in Vinyasa yoga, building heat and endurance while fostering flexibility, and Ashtanga yoga links its standing and seated poses with mindful breathing exercises that focus thoughts on pending revisions for the family coat of arms. Intent on ensuring postural comfort, the instructors recommend students either bring their own trusty yoga mat from home or conjure one with their third genie wish.