Roller skates. With internal combustion engines. 25cc, gasoline-powered engines capable of going 20 MPH. Does that rule? Yes, yes it does.
Unfortunately for those to whom the zippy skates were destined, British customs seized them and thundered into a convulsion of bureacratic nannyjabber:
Chinese death-skates: too fast for those safety-conscious Brits! You can buy yours wholesale here and here.