I came across this article (via Digg) from a 2006 Rethinking Schools journal. The authors lead a before- and after-school program, and their story is about a teachable moment regarding ownership and society. The classroom Lego collection became a battleground as some kids claimed ownership of certain pieces, so the teachers developed a set of exercises and discussion opportunities to help resolve the issue. Over time, this evolved into a better understanding of how rules are formed and how societies function.
I think out-of-school programs play a critical role in helping young people understand society. Because there is less formal structure, there is some room to let the kids form the rules. There is also time to reflect on how changes in those rules affect everyone. Open discussion and free choice cannot go as far in the classroom because there is a necessary structure there. (Of course, there are your "Dead Poet Society" exceptions, but how would those kids have done on their standardized tests??)
One could read the Rethinking Schools article and worry that these teachers are preaching a form of communism - see James Clavell's The Children's Story for a fictional account. However, it is exercises in free thought and debate that allow the students to grow into adults who can appreciate the value of the world they live in without forgetting that it is imperfect.
On a related note, the Afterschool Math PLUS curriculum includes a unit on the built environment which includes a design charette similar to the activity described in the article (building Pike Place Market from Legos). However, the kids using Math PLUS probably have instructors who are promoting cooperation and fair play more directly, since this is a deliberate part of this curriculum. The results that I have seen are great - the kids design wonderful communities (to scale - it is math after all!) and most have social justice built in. So, here is food for thought: is it better to deliberately teach our kids to be fair or better to conduct exercises that let them discover fairness on their own?