Dragon door has a really good selection of articles on body weight exercises. Most can be done with only your body or common items like dowels, or on things like a tree branch. Linkhttp://www.dragondoor.com/articler/mode2/Workouts

Body weight exercises seem to be really underrated right now by most people. One of my exercise goals, once I start working out regularly, is to be able to pull off planche push-ups. It's like a normal push-up, only your feet are kept off the ground for the entire time.