The Wii Fit takes this side effect and makes it into a goal. The package includes a small platform that you step on, balance on, do yoga moves on, etc., while the software coaches you from your TV screen. You can do anything from boxing to yoga to (gasp!) aerobics.
Is my job in jeopardy? Unlikely. Although the Wii Fit will certainly get your heart pumping more than the average video game, it's really only going to benefit fitness amateurs. Anyone who has set foot in a gym will probably find the Wii Fit fun but unchallenging.
Although I haven't used one myself, I can't imagine that a platform (and sometimes the wand) provides enough feedback and motivation for the user to truly learn proper form for exercises. As a first step, however, The Wii Fit, is an impressive application of technology to health. Surely as the level of technology increases, so will the similarity of the product to a true fitness experience.