This year more and more people around the world are joining the Earth hour. All you have to do is turn off the lights for one hour today (Sat 28 mar). In Brazil it will be from 20:30 to 21:30. Many cities in Brazil have joined the project and will turn off the lights of its famous monuments and public buildings. My kids told me they wanted to participate after watching a Brazilian commercial (included here). You know, I think the idea is fabulous, bringing people from around the world together and creating a reflection moment.
http://www.earthhour.org/home/