Sure, you can celebrate Earth Day this Thursday by eating in the dark at your favorite restaurant, but you can also stay home, keep the power on and watch television, after which you can work on growing your own food in your backyard plot of earth. In celebration of Earth Day, PBS is airing DIRT! The Movie this evening. Narrated by Jamie Lee Curtis (be grateful it is not Activia! The Movie), the award-winning documentary explores the history of, well, dirt. Specifically, “how four billion years of evolution have created the dirt that recycles our water, gives us food, provides us shelter and can be used as a source of medicine, beauty and culture.” There's a nice back-to-basics feel to this, of course, as without good dirt you can't grow good food, etc. Your sustainability conversation starts here.