I don't watch it regularly, and like 'chair, I am not into cars. But the presenters are very charismatic and entertaining, so much so, that it's very accessible to pretty much anyone, and very enjoyable too.
I need to see the plane-race thing someone mentioned...
They had two similar contest like the plane race actually. One was that Jeremy Clarkson toke a car to (I think) a French city and the other two toke the buss and a plane to the same city. The other one started the same with Jeremy Clarkson driving a new car but this time the other two could only use common transportation like bus, train and such. No luxury or expensive transportation was allowed. This time the goal was another city further away from the UK.
My favourite one was where they drove accross either america or alabama at least..i forget but the point was they got to write on each others cars things like "nascar sucks" and "I'm Bi" and "Hillary for President". They nearly get killed.