For the Earth? On which you live?
If yes, then just turn off the light for 60 lightly minutes and enjoy your life without electricity. A pleasant talk with your friend, a candle-light dinner with your partner, a great party with whomever you want to, do it and take part in this movement. It couldn’t hurt, right?
You can also download some goodies from it’s official site, earthhour.org. Check them out!