How get my daily 500 calorie burn in?

I've been trying to lose weight for quite some time now, and I have made some progress, but I still want to lose 10lbs before I will be totally satisfied. I REALLLYYY want to lose it by June 2-3.. and I think with hard work I can do it, even if the last lbs are the hardest :/ Anyway, I have been slacking off lately due to Easter, birthdays, graduations, and other celebrations (darn cake...) and I was planning to really crack down tomorrow. Well, my luck, I was practicing my front aerials on my trampoline and something went wrong and I stiffened my leg and rammed it into the trampoline bed, which I am pretty sure hyper extended it, if not its badly stretched. Awesome. So, theres no way I can run or bike for at least the next few days. I don't have any time to waste whatsoever, so Im still going to try and get in my 500 calorie burn per day, I just don't quite know how. I am going to be staying home from school since I can barely walk, and my mom will probably make me stay in bed most of the day. I am planning on eating nothing but fruits and veggies for the most part, and I was considering doing situps or pushupsb (i can kinda tuck my leg above the other one so it doesnt hurt..its hard but I can manage) to burn calories. I know they burn close to absolutely nothing, but it's better than laying in bed all day. So, how many situps/ pushups would it take to burn 500 cals? Or if you have a better idea, please share. Thanks for reading, sorry it was so long. And please no bashing, only answer if you can help (I really would appreciate it!) Thanks!