A couple days ago, Bill McKibben, co-founder of 350.org and the Tar Sands Action, stopped in at the Occupy Wall Street protests to lead a teach-in about climate, corporate corruption and the KeystoneXL pipeline. Here's a video from his speech (because the Police won't let the protestors have any kind of amplification, they use a system called "the people's mic" where everybody in the crowd repeats the words the speaker says.)