I found that EASE instrument building was a great activity for this population. We made maracas and students shook them. We spend a whole ease lesson just experimenting the rice and pasta. Take some rice, beans or pasta and put them in a box or bucket, then let the students touch the beans/rice/pasta. You could then have the students put the items in a bottle to create a shaker. Then students will have made instruments that they can use to make music and compose or explore music.