I was reading about a knee brace that generates power as a person walks, which can be used to charge a cell phone and has possible applications for prosthetic limbs. It's all over the news, and there's a picture which I'll be happy to find a link for tomorrow. They did say that the prototype is larger than they would like. So they have to work on that.
I was thinking about how useful it would be to have a source of power that could regenerate my power chair, as it went along. For some reason I'm getting images of my cat running a treadmill alongside my chair. Considering his nap time to work ratio, I'm not very optimistic about that as the power source.
UPDATE: Here's a link to an article and photo.
And I also found this post talking about the Flash's Cosmic Treadmill, a time travel device that you use by running on a treadmill. I love it when the scifi images from the past crop up in new technology.