Can a pill replace an hour of exercise? A new "Miracle Pill" is being touted as able to do just that. According to Calorie Lab:

.......scientists are claiming to have developed an "exercise pill" which dupes your cells into believing that your body, while at rest, is actually exerting all kinds of serious effort, thus triggering the same increased rate of fat-burnoff that takes place naturally when you exercise vigorously. The result is that you burn calories at a terrific rate without being required to actually expend any great effort.

The Science Blog explains how ot works, at least in mice:

By giving ordinary adult mice a drug - a synthetic designed to mimic fat - Salk Institute scientist Dr. Ronald M. Evans is now able to chemically switch on PPAR-d, the master regulator that controls the ability of cells to burn fat. Even when the mice are not active, turning on the chemical switch activates the same fat-burning process that occurs during exercise.

Never tried on humans, one has to wonder if it would really work. We also have to worry about side effects and risks.