For a start,you can watch this video
http://hk.youtube.com/watch?v=-qczUcQ-VjM&NR=1

it's a campaign held since 2007,where some countries had their cities off lights for one hour,while some few minutes or so,to save the earth from climate changes...at least a lil...
after the campaign,sydney found that they have save up 10% of their country's coal usage,which means avoided a huge number of co2 and other bad gasses emission.

it's the least we could do for our earth now...so please act..
the date is tommorrow...march 29th~!!

to register yourself,
http://www.earthhour.org/about/supporters

please spread the words!

p/s:mod,please forward this topic to appropriate forum,thank you..
or please make it the big title