The Iao Theater is a quaint historical theater with lots of charm and extremely friendly people.  The productions use all local talent from Maui.  The Maui OnStage staff are the custodians of the theater and they love to give tours to anyone who asks.  If you're at the theater and the door is locked, just knock on one of the office doors and ask for a tour.  Or, better yet, if you're in town when there is a play or concert happening, go.