The description on Walmart.com states:
BMI Check: BMI, or Body Mass Index, is a measure of body fat based on height and weight that is the standard used by agencies such as the World Health Organization and the National Institute of Health. To check your BMI, you'll enter your height then stand on the Wii Balance Board and let it read your weight.
Curious how accurate it weighs people???
Otherwise, if it gets people off the couch, than great