TRX or Total Resistance Exercise is probably the best investment I made as far as exercise is concerned. You can do a complete body workout on the TRX.
How it works!
It's very similar to body weight exercises where you would use your body weight as "weights". The slight difference is that there are straps involved & most of the time you work at various angles to the ground. So the stronger you become, the more you can adjust the angles to make it harder or easier. It's great for your everyday person, as well as Elite athletes.
Check out my clip for doing should exercise.