Hey, I'm sure a few people know of it.
http://www.dreamviews.com
I've tried this a few good times now, but the other night i believe a had my first experience!
In my dream I was unicycling down a steep hill with a long winding rough dirt trail along it, and as I declined I picked up more and more speed. I was about to attempt to slow down but then I decided, "This is crazy, I must be dreaming." I sped around a tight corner at a very tight angle and it felt amazing to do it, but then as I rounded off from the corner I went over a bump that launched me about a meter in the air and towards a gap in the track. Instincts took over and I lost lucidity but the rest of the dream was enjoyable, from my science teacher riding a penny farthing but not picking up enough speed and rolling back off into some bushes to rebuilding my falling apart unicycle, which I somehow lost my pedals a few miles back. I also screwed a screw between my eyes into a little hole so my face didn't come loose, although that was weird.
Oh yeah, I was unicycling as fast as possible because my science class had gone on ahead while I was screwing my face on and I had to catch up.