http://cache.boston.com/universal/site_graphics/blogs/bigpicture/oly_06_06/oly17.jpg

They look like some that I read that are made in Xian, China. Certainly the men in camo contrast to the carnival colors of the monocycles. I wonder what's going on there.

That was posted on a unicycle site. It said that was members of the Chinese army practicing with those as part of the closing ceremony for the Olympics.