bizarre unicycles. unicycles are weird to begin with, but that page details the tall, short, multi-wheeled, etc. recumbant unicycle!
unicycles are usually fixed gear, but several on that page are not: the 1.5 wheeled unicycle and the one-directional unicycle. there are multi-gear unicycles on that page, but you have to stop and change gears manually. not on that page is the "guni," geared unicycle, with gearing inside the hub, which you can (with some skill) change gears while in motion (by toeing/ankling a button on the fork, I think?). there are only two gears, a 1:1 ratio (normal uni) and 1.5:1. (gleaned from this forum discussion of shifting on geared unicycle hubs) thanks for the distraction, ben.