The FSF has been running a campaign against ACTA as it is being mulled over by the office of the US Trade Representative. Bradley Kuhn of the Software Conservancy has a timely reminder to act by submitting a comment now before time runs out. He has plenty of details about how to share your thoughts, including a link to the FSF campaign, as well as sharing his own comment if you need inspiration.
Everyone in USA: Comment against ACTA today! Bradley Kuhn