Earth Day comes only once a year, but you can give Mother Earth a gift every day. The site Earth 911 makes it easy to be environmentally responsible. The Web portal offers ideas on how to recycle old electronics, dispose of hazardous materials, conserve energy, and shop green—and all its tips are tailored to your city or town.Go to: www.earth911.org

And they're off! The participants in this charity biofuel car rally are on their way from the U.S. East Coast to San Jose, Costa Rica. Powered by biodiesel, vegetable oil, waste grease, and other alternative fuels, the vehicles will all be donated to local communities at the end of the rally, which runs until April 27. Along the way, they're stopping to refuel at fast-food diners, farms, factories, and other unlikely pit stops.Go to: http://www.greaseballrally.com

This international conservation event involves 11 leatherback turtles that are "racing" toward feeding areas south of the Galapagos Islands. Pick your favorite of these endangered animals and follow its progress, as tracked by satellite, from April 16 to April 29.Go to: http://greatturtlerace.com

The United Nations Environment Programme has launched a major global tree-planting campaign to encourage people, businesses, and governments to enter tree-planting pledges online. The effort's objective is to plant at least one billion trees worldwide during 2007.Go to: http://www.unep.org/billiontreecampaign

This nature preserve at the University of Wisconsin–Madison protects undeveloped lands along the shore of Lake Mendota. Even if you can't visit it in person, the award-winning interactive map will help you appreciate the qualities of this beautiful slice of nature.Go to: http://www.lakeshorepreserve.wisc.edu

More Than Monarchs.org exists to raise awareness about the devastating impact of illegal logging on the environment and local communities in the Monarch Butterfly Biosphere Reserve in central Mexico. The Web site provides a platform for villagers, community leaders, government officials, and other people to communicate and collaborate toward ending the destruction of forests that support monarch butterfly populations.Go to: http://morethanmonarchs.org

The third annual National Environmental Education Week will take place April 15-22, 2007, culminating with Earth Day on April 22. This site provides information about activities planned for that week.Go to: http://www.eeweek.org/

Lucid Movement is a regularly updated video blog that documents the world through the lens of a high-speed video camera. The resulting videos give viewers unique perspectives on a wide range of phenomena in the world around them, depicting motions that are ordinarily too fast for the human eye to see.Go to: http://www.lucidmovement.com/

Created by the American Society for Microbiology, the Microbe World Web site highlights the increasing importance of microbes in the environment, biotechnology, alternative energy, food science, and healthcare. Designed for science enthusiasts, students, teachers, parents, and the general public, the site features articles, images, audio and video podcasts, RSS feeds, and mobile "phonecasts." Microbe World also offers a comprehensive resources section for educators, parents, and students that includes experiments, lesson plans, and tools for microbiology education.Go to: http://www.microbeworl...

Answers to questions about ozone depletion and the recovery of the ozone hole are now easy to find by researchers, as well as the general public, through a new online index developed by NOAA's Earth System Research Laboratory. The site uses simple graphs and charts to track progress in reducing the threat to Earth's ozone layer—the protective shield that prevents harmful ultraviolet radiation from reaching the surface. A new chart shows which of the harmful gases are declining, which are still increasing, and the overall effect of these changes. Scientists will update the index every year...