If you are working at a desk most of the day, chances are you aren’t getting too much physical activity.
There are exercises geared towards the office setting. They are really good, and it’ll make you feel more energized as you about your day. In the long run, it’ll keep you healthy.
Here are just a couple links to give you an idea. Good Luck, and Have Fun!
http://exercise.about.com/cs/exerciseworkouts/l/blofficeworkout.htm