Yoga sounds like it's so good for you, but I have a bum knee now and it just was too hard to do a lot of the moves/positions.

Someone once had a list of stretches and exercises you could do in bed - I want to search and try to find that. Anything is better than nothing!

EDIT - rats, I can't find it! I searched for a while and just can't find it. If anyone finds it, please let me know!