Let's get physical.
Lock up your daughters. And your Mums, and any Dads who've been showing an uncharacteristic interest in muesli and walking since their last check-up. And your girlfriends and wives (or your beer-bellied boys), and their friends, and those other friends that scoff at your hobby and pointedly declaim their preference for a game of footy down the park and a bit of, you know, fresh air.
In fact, just lock up everyone you know, the young and the old, the fit and the fat, the gamers and the ones who won't even play Wii Sports. Lock them up and throw away they key, because Nintendo is coming for them, and once they get them you'll never get to play on your Wii again. And the fact is - not sure if it's a sad fact or a happy fact, but fact it remains - you're probably going to want to play Wii Fit just as much as the rest of them.
Wii Fit was Nintendo's big surprise at E3 this year: a software suite of fitness exercises and physical minigames that works with a new peripheral, currently called the balance board. The board looks like a set of scales: you stand on it, and it uses pressure sensors to detect your weight distribution. We gave Wii Fit a thorough workout at Nintendo's offices recently (or more accurately, it gave us a workout), and thoroughly enjoyed it. But we're none the wiser as to how useful a fitness tool it will actually be.
To an extent, it doesn't matter. One thing that's always set Nintendo apart is its ability to design hardware that's fun and rewarding to use in itself, and the balance board is a classic example. It's a fantastic piece of kit. It's extremely sturdy, comfortable to use, quick to calibrate, and dumb-foundingly sensitive. The accuracy and speed of its response to the slightest motion, or subtlest shift in your weight, is nothing short of astonishing. Quite frankly, it even makes the Wii remote as it's used in Wii Sports look sluggish and imprecise, and as for the EyeToy, forget it. If the race to create full-blown surfing and skateboarding games for this thing isn't already on, some people need to get fired sharpish.
The demo we played featured eleven minigames in five categories: body tests, muscle stretches, aerobic exercise, yoga poses and balance games. The body tests play elegant little games with simple readouts from the board. One asks you to shift your weight between your legs with ever-increasing accuracy. In another, you have to move your centre of gravity around a square fast, to hit targets. A third tests your balance on one leg - you have to keep a graph tracking your wobbling stature within a range that narrows over time. These are all clever, funny, mercilessly addictive, and great showcases for the hardware.
The balance games are the most videogamey part of the package. Soccer heading was a reaction-test involving frantic lunges to left and right in order to head an accelerating barrage of balls (and dodge flying boots). It was humiliating and impossible, but we played it twice in fits of giggles anyway. The bizarre ski-jump game actually seemed to be a test of our ability to stand up: strangely compelling. In the amazing ball-rolling game, you tilt trays with gentle swaying motions, aiming to drop balls through holes. It's like some perversely brilliant cross between Super Monkey Ball and a roadside drunk-driving test, and we couldn't get enough of it.
But this is all the fun stuff. The hard work starts with aerobics - represented in this demo by a rather pointless and embarrassing minute of hula-ing - and gets serious with muscle stretches and yoga poses. These test your poise and endurance in sequences of stretches and contortions (the balance board's bead on your centre of gravity is so precise that it can tell, to an extent, what your upper body is doing). Afterwards, they offer Big Brain Academy-style statistics and advice on where you are strongest, and where you need work.
Perhaps keeping Nintendo's new senior fanbase in mind, Wii Fit definitely seems to favour of a more sedate style of exercise: think yoga, pilates and tai chi. That's not to say it's easy, and you'll really feel the yoga poses in particular. But based on this demo you shouldn't be expecting it to help you shed pounds or gain muscles. It's all about improving your flexibility, muscle control, reactions and strength.
Whether it can do any more than that for you depends on how the game is structured for long-term use, which was impossible to tell from the demo. Sixty seconds of hip-gyration might be a good ice-breaker at parties, but it's not going to do anything for anybody's waistline or cardiovascular health. If Wii Fit can suggest and monitor a well-thought-out workout regime over time - and if the very brief exercises in the demo are extended in the real thing - then it might actually do some people some good. As it stands though, it's the most fun when it's the least like exercise, and not much more than a cunningly-branded novelty, albeit a technically amazing and very entertaining one.
What Wii Fit will definitely be is huge, with a capital HUGE. Brain Training on the DS cleverly exploited people's insecurities, and sold the idea that games could be improving as well as fun. Wii Sports revolutionised the control interface, and put gaming in a more social and energetic context. Wii Fit takes these two mega-hits, rolls them into one, and throws in a very cool new toy for good measure. Even if it were rubbish it would be a work of uncommon genius, and it's clearly not rubbish.
Pricing has yet to be decided, although we've heard that GBP 50 for a bundle of board and game isn't out of the question, which would be great news. We predict it will fly off the shelves so fast that you'll be lucky to get your hands on one before Christmas. Who knows whether it will make us all fitter in the long run. but one thing's for sure: it will make Nintendo a lot richer.