I've been wondering if anyone else had this problem... but I've had the Wii crash on me while playing. It's not something that happens often, just happened twice, and seems to be related to the console stand.
First time I hardly remember, was when I was playing zelda.
The second time I remember very well. My friend let me borrow Red Steel and it made the wii very noisey. Nothing makes the wii noisey but this almost sounded like an x-box. During a part inside a large hanger, after all the bad-guys were dead I had to walk up to the girlfriend and talk to her. When she started talking everything stopped moving and a soft whistling noise happened. Had to unplug the wii to get it to turn off.
My remedy was to take it off the stand and lay it flat, seems better air flow made the wii less noisey. My friend whom I borrowed it from had the same problems, and also the game FarCry did the same.
I was curious if anyone else experienced this. My friends 360 crashed on him even when I was there so I know consoles do this. But with the wii touted as a low power unit I was taken by surprise.