Here's a video of a sweet boot camp workout. It requires some equipment (though minimal), but it's great for smaller groups. I've used this workout in my boot camps and it's a nice change of pace.

One of my favorite methods uses the "Tabata" protocol. The Tabata protocol uses bodyweight exercises such as squats, lunges, push-ups, crunches, planks, mountain climbers, or really any other bodyweight exercise you can think of.

Check out this workout from Men's Health and Women's Health magazines fitness expert, Craig Ballantyne. It uses his world-famous Turbulence Training workout secrets to help you or your boot camp clients lose belly fat without equipment.