The "95 Theses of Geek Activism" is a great list of 95 ways to use knowledge for good, and to defend freedom with technology.
1 Reclaim the term 'hacker'. If you tinker with electronics, you are a hacker. If you use things in more ways than intended by the manufacturer, you are a hacker. If you build things out of strange, unexpected parts, you are a hacker. Reclaim the term.
2 Violating a license agreement is not theft.
3 All corporations are not on your side.
4 Keep in touch with everyone you can vote for and make sure you know where they stand on the issues you care about.
5 More importantly, make sure they know where you stand on the issues you care about.