15 hottest products of 2008: Wii Fit

Playing video games used to be a fun excuse for sitting on the couch, relaxing and doing much of nothing. Then came along the Nintendo Wii, and its healthy counterpart, the Wii Fit, and video games were sedentary no more.

Losing fat, or lowering your body mass index (BMI) while exercising on the Wii Fit's balance board is supposed to be easy if you're less inclined to go outside or to the gym. Moving around on the small pad may not look like much of a workout, but anyone who has even tried the Nintendo Wii without the Fit, knows that Nintendo has figured out how to make it fun while keeping your heart rate up.

The board measures a user's weight and center of gravity in about 40 different activities such as hula hoop, yoga, snowboarding and pushups, and balance games, strength training and aerobics. The user's "fitness age" can be tracked.

The base system retails for $89.99, and you already have to have a Nintendo Wii to hook the Fit up to. But they can be difficult to find in stores. On the Monday after Thanksgiving, for example, the Wii game console was the most popular product sold on eBay -- 3,017 sold for an average price of $349, according to the New York Times. The Wii Fit was also popular, with 1,305 units sold for an average of $143.