From Ordinary to Extra-Ordinary is the book by Ken Vieth that our current project was obtained. I like this book alot. It is all about challenging my students and taking them past initial drawing into creative thinking and problem solving strategies.
The assignment was to create a drawing which would then be created from "pencils." You can draw anything, but to come up with something that would work well with the idea of the pencils created a challenge. Several students re-started once they realized their basic subject matter was not going to work. It was so interesting to watch this lesson unfold.