So you had a little turkey for dinner. And a few slices of ham. And some mashed potatoes with your mom’s homemade gravy, two servings of stuffing and a piece of pumpkin pie for dessert—with whipped cream on top.

Don’t worry; it’s the holidays—the only time of year you’re supposed to gain a few pounds … or 10. Come New Year’s Day, you’ll have a plan to work it off. This year, the key to that post-holiday weight loss may lie in your boyfriend’s PlayStation 2.

That’s right. In what some might consider the unlikeliest of places—a device that typically facilitates slothfulness, not slenderness—Sony and Nike have collaborated to create Kinetic, an exercise program in the guise of a video game.

An all-in-one fitness program inspired by aerobics, kickboxing, yoga and tai chi, Kinetic allows you to select either individual routines to tone specific areas of the body, or a more challenging 12-week program, which keeps track of workout schedules and monitors progress. Nike’s Motionworks lab has overseen every stage of the game’s development to ensure both the safety and effectiveness of each exercise. You can even choose a personal trainer, the environment in which you work out and the music you exercise to.

It’s true—no expensive gym membership or cute workout clothes necessary.

“Someone who typically wouldn’t go to a class or go to a personal trainer might do it in the comfort of their own home,” says Beth Baumgartner, senior fitness instructor at Nike Motionworks, on the official Kinetic Web site. “And [they’d] probably get somewhere they wouldn’t get on their own.”

According to a statement from Sony, Kinetic is different from traditional workout videos because it measures the force and direction of the player’s movements, analyzes them and provides on-the-sport performance evaluations.

What makes it possible is EyeToy technology. The video camera, released by Sony two years ago, tracks your every motion and makes you part of the game. What’s new is the wide-angle lens attachment, which comes packaged with Kinetic for around $50 and allows the camera to view your whole body as you jump, kick, run and sweat your way back to that pre-Thanksgiving body.

But some fitness professionals are skeptical. “If it actually worked, it could be the best workout product available,” says Jeff Badarello, a personal trainer at 24 Hour Fitness. Still, he says, the most important part of working out is maintaining proper form, and he wonders how carefully Kinetic can monitor the player’s ability to execute the exercises correctly. “I would probably [recommend] it in conjunction with going to the gym,” he says.

Brianne Walterhouse, a 25-year-old teacher from Oakland, says she won’t join a gym because it’s “too freaking expensive.” She thinks Sony and their Nike advisors are onto something. “I’d definitely try [the game],” she says. “I’d much rather be able to get an effective workout at home than have to go through the hassle of getting to the gym all the time.”

Released on Nov. 22, Kinetic comes at a great time for the video game industry, which has long been accused of promoting a sedentary lifestyle among American youth, and has even been blamed in part for the country’s obesity epidemic. Now, it seems the industry finally sees the potential of video games to improve health and fitness rather than take away from it.

It's ok to enjoy those holiday feasts without guilt. Just remember to play your video games.