SargeCorp LLC (NEW), Silver Spring

Even if you're a civilian, the founders of The Sergeant's Program believe there's no excuse for not giving 100 percent. Each sergeant—not trainer—holds each participant accountable for their performance, and that starts with the wardrobe. Everyone wears the program's workout T-shirt, and showing up without it usually results in some extra push-ups. It's not meant to be a punishment, but rather a show of commitment to the program's focus on camaraderie and accountability.

The Sergeant's Program started in 1984, and many of its participants have been attending for a good chunk of that time. The recipe for that enduring success? One-hour classes with a combination of running, calisthenics, aerobics, and strength training. These boot camps unfold five days a week at more than 20 locations across Washington, DC, and its surrounding areas. While the sergeants encourage participants to kick-start their days with early morning sessions, a plethora of evening options are also available.