Apparently, the Japanese manual for the Wii is ridiculously detailed and ultra-safe: don't choke yourself with the nunchuk cable, don't pour orange soda into your Wii, don't swaddle your Wii in blankets like a baby...
Some dude decided to make the Wii and integral part of his fitness regimen. He claims to have lost 10 pounds and be in better shape than ever after playing 30 minutes of Wii sports each day for 6 weeks. Read about it for yourself.