Yesterday, Calvin was able to dress up in costume for school, and participate in a parade. He came home for lunch so that he could change afterwards (otherwise, he'd have to bring his costume to school and change in the bathroom. Coming home was easier). Sometime last week he went to a halloween store that has opened up in our neighborhood, with a friend. He came home with this sombrero. Once I saw it, I said it would be perfect for a mariachi costume, especially since we had most everything for it already. He loved the idea, and here he is, complete with 'Zorro' facial hair. :)
He's planning to dress up like this for trick-or-treat on Sunday afternoon, and again on actual Halloween, when we go to a friend's neighborhood that does night trick-or-treat. I tried teaching him some songs, but he keeps forgetting them.