This has to be one of the coolest grassroots tactics I've ever seen. Listen to this:
(better yet, go to www.truemajority.com and click on Parade. I wanna drive around in the big piggy!!)

THE PARADE GOES ON TOUR TO SEND A MESSAGE TO THE PRESIDENT AND CONGRESS.
EARTH TO BUSH: DON'T ATTACK IRAQ
True Majority Parade: Overview

We are four who have been chosen from around the country to embark on an epic road trip in the name of social awareness and change. We are traveling to major cities and points in between, visually confronting people on the issues of education, environment, and wasteful military spending. Our unique theme vehicles are amazing in generating attention and interest. Our mission is to get people registered to our free web service, which monitors Congress and notifies our members when their voice needs to be heard in Washington. By use of the Internet we aim to strengthen the collective voice of individuals, much like ourselves, who care about current issues but feel disillusioned and detached from the government. If it is thought that social change will only occur in Washinton "when pigs fly" now True Majority offers America "a pig that drives." Be sure to register your name and keep an eye out for the True Crew coming to a city near you.

The four vehicles, listed as they appear on the street, are:

The Natural Gas Vic. A 2001 Ford Crown Victoria, which runs on compressed natural gas is our lead vehicle. It is covered with thousands of tiny people representing the unheard voices of so many Americans. This vehicle plays crowd stopping music and generates bubbles from the bubble master 2000.

The Treeus. A 7 foot tree is mounted on a 2001 Toyota Prius which is a hybrid gas/electric car that gets 48 miles to the gallon, (without the "roof mounted tree" option). With "Reduce our Dependence on Oil" written on the side, we aim to encourage people to branch out and explore alternative energies.

The Mothership. Our RV is our home away from home as we travel across the country. As congress considers resolutions to action in Iraq, the mothership carries a message to the president; "EARTH TO BUSH: DON'T ATTACK IRAQ."

Rolling Piggies. A 1999 Chevrolet Express Van has been transformed into a 12-foot tall piggy bank labeled “Pentagon” representing military spending. It pulls a trailer with a piggy bank 1/10th the first piggy’s size labeled “Education”, which in turn pulls a little-bitty piggy labeled “World Hunger”, which represents America’s paltry humanitarian foreign aid budget.