Crowdrise and Groupon teamed up to present the Earth Day Challenge, to help raise funds for green nonprofits. The organization to raise the most by May 15 gets $25,000 ($15,000 for second place; $10,000 for third). Of course, we celebrate Earth Day every day with our projects initiatives to green homes, communities, and cities. But if you're looking to do something for Earth Day, how about a donation to help fund our projects? Every dollar helps!