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 $29, you get one month of unlimited yoga classes at Three Rivers Yoga Institute in Coraopolis (up to a $75 value).

Open since 1993, Three Rivers’ experienced troupe of body benders imparts fledgling flexibles with position-posing know-how via 22 yoga classes a week. Uplifting mantras waft through the studio air during the 108 Classical Sun Salutations classes, and 36 poses occupy limbs and alleviate muscle frustration in Surya Flow sessions. Stimulating bellies and backs, Alchemy of the Core classes advance core strength through a series of Asana poses and mediations about transforming body coal into diamonds. Mommies-to-be can sooth pregnancy pains with other expectants in Prenatal Yoga classes, and future adults twist and stretch in Kids Yoga, which is dotted with basic poses, games, and music. Classes are scheduled at convenient times including early morning and evening sessions throughout the week. Three Rivers’ expansive studio comfortably welcomes up to 40 sentient stretchers. Shiny bamboo floors and calm taupe walls surround foliage accents, as ceiling fans cool down bodies and extinguish rogue dust bunnies. As an added perk, Grouponers can add a second unlimited month of yoga for $50 (normally $75).