Theory books are an issue I can’t quite figure out yet.  I don’t know if this is good or not, but I don’t have my students work out of theory books.  I remember hating those books when I was growing up, and I would always eventually stop bringing them to lessons.  And I was one of those weird kids who enjoyed homework!  So I figure that if I hated theory books, my students probably will too.  I use a great website that has free theory pages you can print.  I am using some of those and adapting them to my student’s needs.  I do look through the theory books that correspond with my students’ books and make sure I teach the concepts that are important for the songs they are learning.  So I end up making a lot of my own theory pages for my students.  So far, I have enjoyed doing it that way because I can make the pages as easy or hard as I want and I can add things that are more specific to individual needs. 

What do you do for theory?  Have you found a way to make theory fun?