Well, on 7/7/07 there was the Live Earth event, "The concerts for a climate in crisis". Now everyone can do his part, making little changes to each day by day small habits. For example when you search on the net, why don't you change your default google search page to the Neroogle page? You'll "reduce eye strain and save energy while conducting Google searches"...
Here is the explenation of the theory: "Take at look at Google, who gets about 200 million queries a day. Let's assume each query is displayed for about 10 seconds; that means Google is running for about 550,000 hours every day on some desktop. Assuming that users run Google in full screen mode, the shift to a black background will save a total of 15 (74-59) watts. That turns into a global savings of 8.3 Megawatt-hours per day, or about 3000 Megawatt-hours a year. A goodly saving of energy for changing a few color codes."
So cool! :-)