Nice note on the windscreen - if it is just parked.
If they are using it -
Make sure they are in their house, preferably drunk, and the car is parked on its own on the road.
Call the police and ambulance services saying someone has been run over and the driver has run off leaving his car.
Before they arrive jump on the bonnet, denting it, then lie in the road about 5-10 yards in front of the car shouting "Aaaaagh, Aaaaagh come back you bastard" and tell anyone who will listen that he ran in to that house over there.
Job done.