I recently came across this video of a couple of lads riding unicycles in Edinburgh, so thought I would post it here:

Apparently they are part of the Voodoo Unicycle team, who do demonstrations of the esoteric sport of Extreme Unicycling, often at charity events. They are currently organising a 24 hour Extreme Unicycle demonstration event which they hope will set a new world record on 30th and 31st July between the Galleries on the Mound. The event will be raising money for UNICEF. If you would like to make a donation, you can do so here. They are also looking for corporate sponsors, so if you know anyone who would like to sponsor them, they can be contacted here.