Has anyone played the Nintendo Wii Fit yet?

I've been beating myself up with one of these things for three days. I'm stiff and sore but I feel great (and astoundingly I'm already seeing results). So far what I've seen is that the game is remarkably accurate in judging your posture and balance as you do this stuff. The advice it offers (printed and spoken) is very helpful: concentrate more on balance during these exercises than anything else. There's always going to be a few exercises you get good at quickly, and at least one that is just impossible to master. It's that one that you should focus on. At the beginning, that's just a matter of making sure you get the right amount of exercise in the right muscles. As you get into more advanced exercises, though, you can hurt yourself if your balance and posture are off. It's much better to master the beginning exercises before trying to tackle the advanced ones -- when you're regularly earning 3 or 4 stars on the basic ones, then it's okay to move on to the more advanced stuff. Don't switch to a challenge or to a higher difficulty level on an exercise just because it becomes available. Once you find yourself getting bored with the first row of activities in each page, and once you stop feeling sore and stiff from them, move on to tougher versions or tougher exercises. It's also a good idea to split up your workout over the day -- do 20 or 30 minutes early in the day and another 20-30 in the evening. You still get the "work" done but it's less painful overall. Stick with it. This thing's a blast!