Wii Fit is an add on for the Nintendo Wii that includes a balance board and several games and activities that use the balance board and sometimes the Wii controller to give feedback to the user.
Wii Fit probably wont appeal to hardcore fitness geeks and they would probably find it boring. It seems to be targeted at people who find working out boring and so don't normally do it. Wii Fit's activities focus on yoga, strength training, aerobics, and balance games.
When first starting up Wii Fit, a little Wii Fit balance board asks a series of questions and measures one's center of gravity and weight. Then the little bugger issues it's judgement of whether one is fit or fat based on BMI and gives an fitness age to the individual user that maybe be higher or lower than the person's actual age.
My personal experience with the Wii Fit is that it is a fun way to learn Yoga poses and do a little more exercise. My favorite activities are yoga and certain balance games and running in place.
One thing that would make the Wii Fit even better is if one could personalize a routine instead of having to go from pose to pose and activity to activity or even if it had a sort of randomly generated routine such as the fitness routine for Wii Sports but overall it is a great deal of fun and I like the biofeedback when doing yoga to know where my center of gravity should be. I give it an 88% of 100% and maybe the score would go up depending on what else is available to use with Wii Fit in the future.