I've been helping a friend of a friend who owns a local truck detailing business. Mostly the job entails washing and detailing tractor trailer units, but it also includes washing construction equipment. Thursday afternoon, Chris (the owner) offered me a chance to drive one of these to get washed:
A John Deere 950c Crawler Bulldozer. PDF file with specs and more photos can be found here.
It's actually easier to control than I had previously thought (though this one looks pretty intimidating) since the 2 main controls (speed/direction and blade) are joystick-style devices. Much like you'd find in a jetfighter cockpit or arcade game. Though I've been around them before when I worked for a construction firm, I didn't operate any. For the washing/detailing job, we had to move it into the wash bay at the equipment firm. While I didn't plough any dirt, and there wasn't much clearance between the blade and the bay walls, it sure was fun!
Unfortunately, it didn't transform into a giant robot.
Photos from here.