I try to attend a Boot Camp style workout at least once a week. I've found that its a good change of pace from the regular workouts I do and challenges many of my muscles in ways I could not imagine.
The one's I've been attending have been done through my nutrition club but many gyms have been adding them to their workout schedules. I've even seen trainers offer them as personal training classes. If you haven't tried one yet, I suggest you do. Especially when its performed outdoors.
Most Boot Camp Workouts are a variety of body weight exercises, push ups, sit ups, squats, etc. or variations of the same combined with core building, jumping and running. Boot Camps can be done where everyone does the same exercise at the same time or broken into smaller groups and you rotate through different stations, or both.
Its a great way to challenge yourself and improve your cardiovascular health while building your muscle strength.