Body weight, body weight, body weight. Body weight training can be the best exercise for the human body. If done correctly and with the right intensity it can be very effective, very strenuous, very tiring and extremely beneficial. Here is a great video of a young man performing 20 fantastic body weight exercises. He is a gymnast and some of the moves are pretty advanced, (even for me in my younger more flexible days) but he has some great inspiring twists on classic exercises. With body weight training, the basics that need to be covered are some pull ups, push ups, handstands, core work, some tumbling, human flags, levers, single leg work, jumps and any variations to those exercises. One of the greatest parts of exercise is all of the creative ways people find to make it more challenging and difficult. Always trying to make it harder, to strain more, to challenge your self and you body to go as far as you think you can comfortably. Think of ways you can add variety to your routine and make the classic exercises even better. Good luck to you all and challenge your mind as well as your body.