Image from Kotaku
Parkinson's disease is a nerve degenerative disorder that cripples people, making walking difficult and making them tremble like crazy. This woman here, Jo Collinge, was one such victim.
Then 45 minutes of Wii Fit therapy a day (it was a Christmas present), and suddenly, her condition improved, she could walk again, and she could do things other people with Parkinson's can't. I doubt she's completely cured, but this officially puts Wii Fit on Nintendo's list of awesome next to the life-saving Nintendo DS (used as a flashlight in a rescue, used to cure lazy-eye syndrome).