There is a kart track in Milton Keynes (UK) that is frequented occasionally by the odd professional driver... and luckily for us they have a Top Gear Style lap chart. They run 125cc Rotax engined karts, so some fairly serious kit. Alex Brundle (son of Martin) and Sebastien Buemi cheated though - Apparently they had the restrictor plate removed. I believe Wade Eastwood is a stunt and racing driver.
They can all go and suck it though :)