The highlight for Gordy seemed to be when the instructor brought out a box of egg shakers for a song. He had one in his mouth the entire song and he nearly lost it when she took all the eggs away in preparation for the next song.
All in all, I think it was a pretty good experience for him. He really liked being around a bunch of other kids, he liked most of the music, and he had tons of fun playing with all the new toys/instruments. Maybe in a few months when he's a little older we'll go back for another class :)