Like the framework of a mighty skyscraper, the core helps humans hold up the weight of the sky. Stay firm against the firmament with today's Groupon: for $30, you get three classes at RockIt Body Pilates (a $117 value). This Groupon is valid at the Redondo Beach and Manhattan Beach locations.

RockIt Body Pilates' pulse-pounding classes employ dynamic ab-centric exercises to help trim fat, tone muscle, and fortify cores. During 50-minute RockIt Barre classes, upbeat instructors motivate participants as they stretch sinews and kick-start circulation through a fast-paced series of fluid movements that employ the ballet barre for graceful balance, poise, and politely snapped applause. The studio's SPX Proformer classes meld Pilates with aerobic and anaerobic training on a specialized Pilates reformer machine. Students can align joints and burn fat in these supportive group classes, which surge with energizing tunes performed by musically inclined resistance bands. For a more playful workout, RockIt Recess classes engage pupils with a variety of props and plyometric exercises throughout the studio to sculpt fit physiques with the speed and precision of an espresso-fueled Michelangelo.

A flexible schedule allows students with busy days to amble into late-night, morning, and weekend classes to strengthen cores in the pristine, spacious studios. All pupils don tread socks to ensure safety and cleanliness inside, and to disguise famous tootsies from eager foot-philic paparazzi.