Years later I remember sitting there fiddling with a "circuit tester" that Dad had made from an old electrical cord ending in two nails and a little light bulb that would light up if there was a circuit. As it was plugged in, I was testing it on  different spots on my body, legs, etc. with no reaction.  

Then when I put it between my ears. BOOM! It felt like someone had hit me with two hammers.  My mom couldn't stop laughing (because of the expression on my face).  We never did determine if the light went on!