This may be the most improbable and amazing vehicle I've ever seen:
This is another offering from Hammacher Schlemmer. It's a Motorized Monocycle! Conceived in France and manufactured in the Netherlands, this fiberglass framed vehicle seems like a cross between a bicycle and a hamster wheel. It runs on a 31 c.c. engine, can travel up to 25 mph, and can "drive" for up to 2 hours on less than a half-gallon of gas! That translates to over 100 miles per gallon, which is pretty impressive. The catalog explains that it can "negotiate any dense surface such as pavement or grass."
They also warn that it's not street legal, so I'm a little unsure where you are allowed to ride your monocycle. But assuming you were able to pay the $13,000 price tag, (and $800 for shipping), you can probably just ride it in the velodrome in your backyard.