Big banks have been sending you the means to protest their greed for years. You just never realized it.
We all receive junk mail; it's a universal constant, like gravity. And many of the envelopes clogging your mailbox are things like credit card offers and checking account deals from large financial institutions—the same ones whose irresponsibility and greed catalyzed the economic crisis we're currently enjoying. Those banks' actions have sparked the "Occupy" protests around the world and a wave of people moving their money to credit unions, but there's another way to voice discontent. Enclosed with each credit card application is a prepaid weapon for a small protest: a business reply mail envelope.
The banks pay for these in advance, but only if they're sent back. Depending on how heavy and rigid you make it, banks have to pay increasingly more postage. Moreover, someone at the banks have to open these envelopes and read what's inside. Enough envelopes from us, and someone upstairs will have to hear about it. It's a brilliant way to have your voice heard, hit the big banks with a satisfying monetary sting, and cathartically get rid of your junk mail.