In the Victorian era, people made their cores look tight by wearing corsets, which doubled as bulletproof vests during pistol duels. Strengthen your core until it's naturally impervious to bullets instead with today's Groupon for classes at The Pilates Principle.

Choose from the following options:

• For $25, you get five Zumba classes (a $50 value).
• For $37, you get five yoga classes (up to a $75 value).
• For $62, you get five Pilates classes (a $125 value).

The professional staff at The Pilates Principle, led by physical therapist Nuhar Jaleel, teaches Zumba, yoga, and Pilates in a studio decorated with plants, soft lighting, and bright tones. Opt for Zumba, an aerobic exercise in which Latin rhythms conspire with resistance training to dance-sculpt bodies and tone elbows. Fledgling fitness-seekers can also choose five 75-minute classes of athletic-style Ashtanga Yoga, which begin with sun salutations, continue with strategic postures and stretches, and end with improved balance and unimproved clarinet skills. Pilates participants can choose between varying difficulty levels of tower classes, which combine mat work with spring resistance to increase core strength and overall body fitness.