Here is a unicycle exerciser I put together for those days it is just too nasty to go outdoors. I'm working on leg/quads strengthening and this thing really does a job on my legs. In use I stand up and have very little weight on handle bars. Unlike a unicycle on rollers this puts about half my weight on the front and half on the back peddle. This is kind of like an ultimate wheel or peddling a unicycle uphill and downhill at the very same time. It doesn't take long to turn my legs to jelly. Also with the speedo it works well to track my improvement in speed cycling and general peddling coordination. With the speedo calibrated to a 36" unicycle I've hit 21.9 mph (that's 152mm cranks at 205 rpm) and getting better as time goes on. I don't really plan on riding my uni at that speed but the extra speed ability is always a good thing to have in reserve.

I also made a longer seat post adapter so a normal unicycle saddle would fit on it for general peddling coordination and testing different saddles.

All of the parts I picked up at no cost except for the "Waterproof 14 Function LCD Bike Bicycle Odometer Speedometer Cycling Speed Meter" and that cost me $2.79 delivered to my front door.