In need of exercise

At last, the sun's shining. I am so in need of exercise; for the last two weeks or so, the rain has been to heavy to allow walking to be a pleasant experience. And now I can't go out until I've finished marking exams. My muscles are twitching for lack of exercise. The biggest problem, of course, is that exam marking makes you really, really, really hungry... and no time to exercise off the extra calories!