The pilot stated that he and his son, who also held a pilot's certificate, had conducted several practice instrument approaches at three different airports prior to stopping for lunch. They departed back to their home airport, and on the base leg of the traffic pattern for landing, experienced a total loss of engine power. The pilot noted that the fuel selector was on the left wing tank, and the corresponding fuel quantity gauge indicated that the tank was empty. The pilot switched the fuel selector to the right tank, attempted a restart, but the engine did not restart. The pilot's son conducted a forced landing to a road, resulting in substantial damage to the fuselage, empennage, horizontal stabilizer, and rudder. Postaccident examination by a Federal Aviation Administration inspector revealed that the left fuel tank contained less than one pint of fuel, and the right fuel tank contained approximately 6 gallons.