Wii Fit
The good news is, I didn't gain fifteen pounds in a week after all! The bad news is, I've been overweight the whole time. As it turns out, simple laws of gravity and physics win out when the balance board is placed as-is on carpet; the included plastic foot extenders are pretty much required for any semblance of accuracy. So, while this may not bode well for my personal health, it does reassure me about the game mechanics and engineering, which is really more important to me anyway.
In general, I am impressed by the ability of Wii Fit's exercises and "balance games" to challenge me physically, not because this is hard, but because it is a video game. It's actually gotten me to try and re-try a bunch of stuff just for the sake of my own success, like skiing and ball-table-tilting minigames, where in the process I felt myself at least slightly physically stressed. I don't know if I'm going to get anywhere, but it's fairly fun.
Progress: Slightly overweight