Riverdale Country School in New York cooperated with IDEO and developed The Design Thinking Toolkit for Educators.
It provides guidance through the five phases of the design process. It outlines a sequence of steps that leads from defining a challenge to building a solution. The toolkit offers a variety of instructional methods to choose from, including concise explanations, useful suggestions and tips.
You can download the toolkit for free here (registration is required) and also find other interesting material on the website.