I worked for a short while in a school for autistic kids.

I could give you an account of a lesson (or sequence of lessons) I did with a group of 12 year olds that seemed to work.

However I'm not sure if that's the sort of thing you want. Basically what I did was get them to focus on a piece of music (Mr Froggy went a courtin'), and we all made our own contribution towards the presentation of it.

Also as I remember we wrote 'raps' about what we had done that day to the sound of a drum machine. This proved to be good for children who had developed ways of avoiding communicating.

I'm no expert as you can probably tell. best of luck!