You already: Take the stairs instead of the elevator (20 calories for 2 minutes).
You should also: Park in the furthest spot in the parking lot to squeeze in extra steps between your car and your office, the grocery store and the mall (22 calories for 7 minutes). Add a lunchtime stroll (67 calories for 15 minutes) to walk off 109 calories over the course of a day.
Bonus tip: Bob says that wearing a pedometer (discreetly, of course) can motivate you to rack up extra steps and calories.
Next: 8 ways to burn calories while giving back