I didn't make these. But I rode all of them at Bike Fetish Day this past weekend and fell in love.
This cruiser has 36" unicycle wheels and a coaster brake. It's like driving a leather couch around the block:
The lucky owner is the grinning fellow holding the handlebars. If it was my bike, I'd be smiling too.
This one is also made from unicycles. It has two pivot points - one at the handlebars and one at the saddle. Like a "swing" bike but way harder to ride. I got about 30 feet in a wavy line before wiping out, did it over and over, and loved every second.
And this one was made by hand from scavenged parts. The builder is the guy wearing a plaid shirt in the photo. The two seats face opposite directions. Two riders are required - each one operates one wheel. To go in a straight line, someone has to pedal backwards. I got into it with my wife and we almost crashed into several parked cars...
This was a great time, hats off to all the builders and mechanics that showed up with some really sick bikes. Now I want to make one too.