A co-worker showed me this bike with a sealed hub, continuously-variable transmission based on Leonardo DaVinci's sketches. WOW - is this really new, or have I just never heard of it before? I know Audi's have had variable trannies, and my old lawn tractor has one, but I've never seen one small/light enough for a bike. Now my brain is flashing with images of a fixed version for a unicycle!!
More here: http://www.ellsworthride.com/