hmm body weight execizes...
- regular push ups
- military push ups (hands shoulder approx. under you shoulders as you come down keep your elbows at your sides)
- diamond push ups (place your hands under your chest making a triangle shape (these are hard))
- tiger push ups (feet and hands well apart ass in the air, move the forehead towards the floor between your hands then your nose, chin, chest then lift your head up you want to take your time on these, slow movement(sort of like a tiger, these are fun))
- 'noname' push ups

(hands a good meter apart, fingers pointing outwards, down and up like normal, good for the chest)
- crunches
- crunches with your feet of the ground your legs making an angle of 90 degrees
- crunches with your legs horizontal just of the ground
- keeping your legs straight and horizontal lift them of the ground till they are vertical then push you hips of the ground then back to beginning
- dips, for triceps find a low table place your hands on it with your back turned, legs straight and ass not supported (hmm that's a hard one to describe)
ooh a nice one I learned at kung fu class get a short thick stick, one you can grasp, fasten a string to it that almost reaches the floor from your shoulders attach a weight (not too heavy) now hold the stick with extended arms in front of you and roll the string with the weight up and down, this is murder on your forearms and shoulders.
and one thing you might be able to convince your parents to get is a pull up bar they're not very expensive, with that and the exercizes above you can work your upper body till you can't pick up a glass of water to take a drink.