Ep # 313, Hooked on Monkey Phonics (the one with the home-schooled kids):
I just noticed that when Papa Cutzwald comes into the auditorium, he pulls the plug out of the wall, and Dio's instruments go dead. He demands to know where his children are, and young Mark grabs the mic which does a characteristic squeal, and Mark starts using it. Wait - didn't his dad just unplug it?
Ok, I've got too much time on my hands this weekend. ;)