There's probably one in your neighborhood, an amateur inventor or eccentric engineer trying to fabricate the next big gizmo. Host and jack-of-all-trades builder John Bowler travels across America to meet these ``mad scientists'' and to check out their outrageous projects, from a jet-powered motorbike and rock-crawling machine to a basketball-playing robot and a giant telephone pole seesaw. Bowler then challenges the builders to come up with an upgraded version of their inventions and works side by side with them over two days to get it done. After a testing phase, the creations are revealed -- warts and all -- to a local audience.