Good question about calories burned. I have no clue. I was thinking more about how the unicycle worked the core and helping to strengthen your balance. I thought it could be interesting to do, especially since I'm not big into group exercising (like yoga, zumba, etc.). I prefer solitary activities.
Calories burned from unicycling: www.sparkpeople.com/resource/calories_burn
The website I looked at: www.unicycle.com/home/