My 2 yeard old son has an extreme fascination with automobiles and big vehicles. He loves it whenever we're on the road and joyriding. The busy highways and streets entertains him so much that he shrieks in glee (with matching claps) everytime a truck, a bus, a jeep, train and a bike passes by. The big ones are his favorites though. So even if it's a septic tank cleaner truck, he'd surely be delighted upon sighting. Even the sky and the river do not escape his attention because he loves seeing airplanes and boats, too.