My usb servo controller has arrived from www.phidgets.com in Canada and I’ve managed to get it to jiggle the servo around on demand, which is enough to do what I have in mind. To make this noodling more interesting for spectators, a plastic smurf has been blu-tacked onto the servo shaft.
Best suggestion so far - couple the servo to a motion detector and a stuffed beaver from Get Stuffed taxidermists. Then you can have the beaver turn to track and stare at people in the room…. creepy!