I tried a helmet cam this time just to see how it would work. I zip-tied a camcorder onto a bike helmet. It looks ridiculous and you can't really forget its there, but you can indeed move around rather freely.
I experimented to see how well it would work. I think with a smaller device, like the Veho Muvi, it could work well assuming that the video quality is usable. I ordered one during black friday for $50, so I will trying it out shortly. The nice thing about the Muvi is that is is thumb-sized and weighs only 50 grams - it is small enough to velcro to hat. This also has the advantage that it should be unnoticeable to the casual observer.
Great videos - they will be very difficult to judge this time for sure!