I got Sam some snazzy headphones that actually stay on her head. Plugged them into a CD player we got from freecycle and she was a dancing machine! She kept yelling at Jeremy and me to dance to the music too. We'd reply "We can't hear it, only you can."
To which she'd respond, "HUH?!?"
This is how she danced. Scroll down at an even pace to get the full effect: