The Wildcrafting game and Shanleya's Quest book mentioned by Anne are great...but I doubt they would hold up with a twelve year old. We are using them with my eight year old grandson. The cooperative nature of the game frustrates him at times, because he is bent on winning a game where there are no "winners", but we all learn from it and usually have fun. I love Shanleya's Quest, but even though any age can learn from it, it is definitely geared toward a younger crowd. I love the making triangles suggestion above: interaction with peers and critical thinking and permaculture all rolled into one. And I love the perennial early and late summer harvestable food forest idea.