I used to teach English as A Foreign Language and wrote a song to teach the use of 'used to'. It was called 'My Little Brother' and while it was deeply embarassing in an artistic sense, it seemed to do the trick in getting across all the things he used to do. (Actually, he didn't used to do any of them because I made it all up, but that is beside the point)

I taped it and played it to the students, used worksheets so they could listen to the lyrics and fill in the gaps, asked questions using 'used to' to check comprehension and got them to tell each other about 'The Things They Used To Do' which, coincidentally, is a blues song but that is also beside the point.