Howard Finster inspired Self Portrait. Works great with older students too. I ask them to begin writing in concentric spirals around the head and paper with a continuous stream of thought triggered by a prompt such as I dream about .
So you want to do some work with chalk pastels? Here's a wonderful place to start: 100 Free Art Lessons at Hodgepodge - Art for All Ages (Chalk Pastels & Acrylics) Plenty of helpful techniques, links to tutorials and, projects/lessons!