If you have a doorway I'd get a pullup bar for the doorway. This kind will not require screws: http://amzn.to/L50wSF
I have this kind...
You can get a lot of great workouts over at http://bodyrock.tv
here is a workout I use quite a bit
5 sets.. minimal rest between
All exercises are 1 set.. no rest between different excercises
8 reps pullups
10 push ups
15 body weight squats: http://www.acefitness.org/exerciselibrary/135/bodyweight-squat
Adjust the reps and the # of sets to your fitness level
Here is another workout:
(do 5 sets)
If you can get some 10 pound dumbells you could do some "man makers"
1 man maker:
do 10 to 15 man-makers
There are just a few ideas to get you started. Here is another idea... start homesteading and producing food on your land (if you have room) ... it's a lot of hard work and you'll get a lot of practical exercise doing it. Start by making a garden and go from there.
Just some ideas.