This Saturday, people around the world will attend more than 5,000 parties in honor of a much idolized, much abused celeb-of-the-moment. No, it's not Princess Di. These parties aim to help the planet, by committing the guests to work against climate change. It's the first time the political house party has ever been used globally, according to the organizers, and it's reached at least 114 countries so far, including Bosnia, Sierra Leone and the Philippines. (Note the rather severe troubles facing people in those countries. So, those of you thinking of not bothering because you have your own problems to deal with? You might want to think again.) Organized by Avaaz (which I've written about in this space before) and MoveOn, the house parties will coincide with the Live Earth concert. Big fat global concert events don't always accomplish much. (Remember Live Aid? Or worse, the dreadful "Feed the World" theme song? Block that 80s flashback!) But the organizers of these house parties believe Live Earth can be different, and they're aiming to, according to Ricken Patel, executive director of Avaaz, "turn the moment into a movement." Party guests will pledge not only to change consumption habits but more importantly, to engage in political action on this issue. They'll agree to pressure their governments to sign on to a global climate treaty agreeing to a 90% reduction in emissions over the next generation. What are you doing Saturday night?