This is starting to get exciting.

Five or six of us are hunched around a table in a small Washington office, shouting into phones and pecking away at keyboards as we count down toward the Saturday beginning of what looks like it will be the largest civil disobedience protest in the history of the American environmental movement.

We’ve got 2,000 people signed up to come to Washington and get arrested outside the White House between August 20 and September 3, all in an effort to persuade President Obama not to grant a permit for a new pipeline from the tar sands of Canada.

As momentum builds, we’re hearing from the famous and powerful: the wonderful Bernie Sanders just offered up a blogpost pointing out how many more jobs we’d create if we concentrated on clean energy; and the dynamic actor Mark Ruffalo chipped in a heartfelt video imploring people to head to Washington for the protest.

But it’s just as exciting to see the stream of inspiring commitments coming in from four Montana grandmothers (one of whom just happens to be Margot Kidder, otherwise known as Lois Lane), or a New York City college student who felt the hope of Obama’s 2008 victory, and also a little of the frustration many of us have shared since, pointing out the many times the president has “backed down from what could have been transformative confrontations with the defenders of the status quo.” Which is exactly why so many of us will be wearing our Obama ’08 buttons when we get arrested: we want desperately to conjure up the surge of joy that came with that campaign.

For me, though, the big thrill of the day was seeing a blog post from my junior high school biology teacher, Fran Ludwig. She’s emerged in recent years as a great Massachusetts leader of the climate movement, and she managed to capture perfectly the message we’re trying to spread.

She says, "I'm going to Washington and risking arrest because, in spite of the efforts of concerned individuals and communities to live in a more sustainable way, government policy is the only way to achieve the large-scale change we need to avert the worst outcome of rampant climate change. The approval of the Keystone XL is exclusively up to President Obama. I hope to add my presence to thousands of others in Washington (and hundreds of thousands in the U.S. and across the planet) to say: Enough! We need to take a stand against fossil fuel now!!"

By Saturday morning, if all goes according to plan, I’ll be in jail, along with the first wave of a hundred or so protesters. But by no means the last—we’ll keep this protest alive till Labor Day Weekend, and then hand it off to the Canadians, who plan mass civil disobedience of their own in September.

And did I tell you we just heard from friends in Turkey? They’re planning to deliver their protest to the Canadian consulate this weekend—and they’ve spurred many others around the world in the same direction.

As I said, it’s starting to get interesting. If you want in on the fun, go to tarsandsaction.org

Bill McKibben wrote this article for YES! Magazine, a national, nonprofit media organization that fuses powerful ideas and practical actions. Bill is a YES! Magazine contributing editor.