The Grist article linked by Mark_R is a worthy read.

The thing that always bothers me about the modern (read: urban) world is lack of access to all the raw materiel, unprocessed and unmerchandised, that is the foundation of what has been built. Access to this materiel, and the tools to manipulate it, and the freedom to experiment and imagine, is what the next generation needs to remake and rebuild civilization to meet the coming challenges that we can hardly envision.

On the subject of saws: I have found that an excellent introductory tool is a simple hacksaw with a 24 tpi blade. Serious injury is practically impossible, and yet with a bit of encouragement kids discover they can cut literally anything with a bit of patience and perseverance. And when that light comes on, a path of possibilities ...