Oscar-winning songwriter Melissa Etheridge, who called Dubya a criminal and said (if I heard correctly) he should be impeached, and Robert F. Kennedy Jr. of the Waterkeepers Alliance, who went on a major rant.

Here is how The Nation recorded it:

But the true stars of the day -- no offense to Kanye, Kelly, and Jon -- were the likes of Robert Kennedy, Jr., whose rousing call for Live Earthers to take their eco-consciousness to the voting booth was one of the day's more exciting moements (sic); and, of course, Gore himself, who was greeted with wild cheers every time he took the stage. Kennedy wasted no time before laying into "the oil industry and the coal industry and their indentured servants" on Capitol Hill, and reminded the crowd that while the little things done around the house can help, "the most important thing you can do is get involved in the political process and get ride of these corporate toadies." "This is treason," he said with a growl, "and we need to start to treating them like traitors."

A clip turned up on YouTube, but it was ordered taken down ("This video is no longer available due to a copyright claim by Microsoft Network"). Here's an audio-only version.

And actually, MSN has a shorter video interview clip with RFK Jr., which covers off most of his main points.

Addendum

Here's a transcript of Kennedy's remarks, via BradBlog and truthout:

Now you've heard today a lot of people say that there are many little things that you all can do today to avert climate change on your own. But I will tell you this, it is more important than buying compact flourescent light bulbs or than buying a fuel efficient automobile. The most important thing you can do is to get involved in the political process and get rid of all of these rotten politicians that we have in Washington D.C., who are nothing more than corporate toadies for companies like Exxon and Southern Company, these villainous companies that consistently put their private financial interest ahead of American interest and ahead of the interest of all of humanity. This is treason and we need to start treating them now as traitors.

And they have their slick public relations firms and their phony think tanks in Washington D.C. and their crooked scientists who are lying to the American people day after day after day. And we have a press that has completely let down American Democracy. That's giving us Ana Nicole Smith and Paris Hilton instead of the issues that we need to understand to make rational decisions in a democracy - like global warming.