Do you have a gym membership, and if so, do you use it? Most of us sign up with the best of intentions, but now use that key fob to access the smoothie bar or do a furtive 20 minutes on the treadmill every few weeks. We're too busy at work to fit in fitness, even if we know it would do us -- and our productivity
-- a lot of good. Fortunately, it turns out, we don't have to leave the office to get in a workout.