The Planetary Society is sponsoring an effort to send a DVD with messages from Earth aboard the NASA spacecraft Phoenix, which will land on the arctic Martian surface in May 2008. The DVD, specially designed to last hundreds to thousands of years, will contain a sampling of space literature from famous scientists and science fiction writers as well as a personal recorded message from Carl Sagan (mp3). Between now and Monday, February 12, you can sign your name to the DVD and receive an official participation certificate by going to the Messages from Earth website. See NASA's Mars Exploration Program website for more info on the expedition.