Do you have free weights at home? even if you have a few, they'll help.
Do lots of push up and squats.
When doing pushups. One day do push ups one way- with your hands in a fixed position. Then next time you do pushups, place your hands on a different place than last time- either farther apart or closer together than the last time.
When doing squats switch it up also, just shift the position of your feet when you do different sets on different days.
Crunches...lots.
If you have some light free-weights... a 10lbs weight is best for this-
Hold the weight up to your chest with both arms- keep feet seperate for balance, and dip on 45 degree angles left and right- maybe leaning back everynow n then un sort of u motion from side to side.
Dont lean too much to either side though, keep your body upright generally.
Shadow box- google it for more info- its simple. burn tons of calories.
do all of these in fairly quick succesion (not in this order) and you have yourself a pretty decent at-home fat burn workout. improbably missing a few thigns, but u get the jist of it.