Earth Day is an international celebration of the environment, usually accompanied by various polution cleanups and things like that. My AmeriCorps team is going up to Seattle tomorrow to join a huge Earth Day celebration and service project. The governor is probably going to come, and we're going to be cleaning up and getting ready a beach and state park for the summer months. Other Earth Day projects I've been involved in have been trail maintenance in a national forest, a streambed rehabilitation, and tree planting in a park, even though that's usually reserved for Arbor Day.