Critical Thinking class... not one class but on going taught at an early age right along with Math, Reading, etc.
Teach kids and then adults logical fallacies, etc. I actually believe this is one of the most important things we could ever do. A lot of people have Utopian ideas they believe can save the world and solve "big" problems, but they all have one common thing that can stop them. That thing is a population that for the majority has never been taught critical thinking. They've heard the words and they may have heard a few speeches about it, but they don't TRULY understand it. If the population at large understood this then I do believe the world would be a very different place and some of these "big" ideas to solve "big" problems might actually be achievable.