I recently read an interesting article, The Puppet Master, about the guy who does Elmo's voice. His name is Kevin Clash, and he's a Baltimore native. He's also a six-foot-tall, African-American baritone--not someone you might associate with that annoying, high-pitched Elmo voice.
Anyway, there is a documentary about Clash's life, Being Elmo, that's out in theatres now. I don't see that it's playing in our area, but if it was, and I had a babysitter, I'd check it out!