You've probably already heard of the repetitive and sometimes ridiculous attacks against Wikileaks. If you believe in freedom of speech and want to defend it, you can sign the petition against these attacks
here. It's free and takes only a matter of seconds (and you can use a false email address if you don't want to give yours).
The last time I checked, there was over 633,000 names on the petition. Let's reach 1,000,000 !