Building a sturdy core of toned abdominal muscles is one of many ways to maintain good posture, along with overstarching your T-shirts and sleeping inside an air vent. Get your head out of the ductwork with today's Groupon: for $49, you get five Pilates and fitness classes at Coreology Fitness in Rolling Hills Estates (up to a $135 value).

Coreology Fitness dedicates its fitness efforts to reshaping visitors of all skill levels with classes that enlist encouraging instruction as well as muscle-toning equipment. Heavily populating the studio's schedule, SPX Pilates sessions update the traditional Pilates regimen by introducing the Megaformer, a contraption of spring-resisted parts more intricate than a Swiss Army knife, though with fewer wine-drinking accessories. The 45-minute workout utilizes the machine for a series of challenging exercises that engage a host of muscle groups. Metabolisms skyrocket to hummingbird levels, and students steadily improve their strength, stamina, and flexibility over time. Waves of invigorating music fill the 60-minute Coreology cardio sessions as instructors incorporate kickboxing techniques, agility drills, and half-marathons into a pulse-hoisting workout, and Barre-ology introduces a ballet barre into a regimen of light resistance exercises, sculpting graceful, toned, and slender limbs to rival a New York City Ballet–caliber swan.