http://tor.eff.org/overview.html.en
Tor might interest you. "Tor hides you among the other users on the network, so the more populous and diverse the user base for Tor is, the more your anonymity will be protected."
Which means you're contributing by simply being there
The downside may be that if you are using it to surf 4chan in order to troll, the probability of you coming across permabanned IPS is pretty high. But overall it's a great tool for anonymous surfing.