Collaboration in School

I feel that collaboration is a very neccessary part of schooling that is often over looked. I just attended a high school graduation and every speaker talked about how it was not just the course materials that were learned but life lessons that went along with learning. In "the real world" people are forced to work together and for other people all the time. If we as teachers do not teach these lessons, not to mention the deeper learning of course materials, then we are not doing an adaquate job preparing our students for the future.