You lay down on this Argentine-designed Cheetah trike and make humping motions to make it go.
More at Treehugger. Video of Pablo Lopez's "Pardo" device in action might be fun to watch.
Comments:
Does it go "Ahh" or "Unnnnh" with each pump? Seriously, unless this is being ridden at Burning Man I can't see anyone riding this wheeled sex toy though I would imagine it would really work your abs hard (hehe, I said hard!). I'mma gonna stop now.