If the idea of a treadmill desk won't work for you because you don't have the space for it, consider the Stamina InMotion E1000 Elliptical Trainer. Of course, you can simply stand up while you do work to burn calories, but with an elliptical trainer under your desk you can burn even more calories. It has adjustable tension so you can vary the intensity of your workout as needed. It's also pretty quiet so it won't bother your mates if you're planning to use it in the office.
$120 Buy
