"teach-ins". There is nothing wrong with sharing knowledge but keep your head and beware of ideologues. (If I ever find myself in a crowd that is asked to robotically repeat what the girl or the boy behind the bullhorn is saying, I will walk.)
(It doesn't hurt to also pay attention to what the man with the funny accent is saying here: http://www.youtube.com/watch?v=5gnpCqsXE8g&feature=youtu... )