I like the Megger test. You get the apprentice to hold the leads then you spin the handle to "make sure the Megger is working"!
When I was still in the service we would do something like this when the ship had been out to sea for a few weeks. We would take a megger, have the first guy hold one lead in his hand, two or three guys holding hands in a line, place a fluroescent bulb in the hand of the last guy, two or three guys after the bulb and the last guy holding the other megger lead. Senior guy gets to spin the handle while the bulb lights up. Didn't hurt much until you started or stopped.