For just one hour at 8.30pm - turn it all off and have a warm fuzzy feeling that the simple act of flicking a switch will make an enormous difference to our Earth.
Shock horror gasp - no phone, no lights or no internet for a whole hour? Oh my goodness - what is there do?
Well, you could sit around and twiddle your thumbs and count the seconds backwards from 3600. Or, you could see that there's a whole lot of fun that can be had in 60 minutes in the dark - you know what I mean.
Whether you choose to do any or all of these, or decide that you're just going to call it an early night and catch up on some sleep - you'll know that by switching off your lights, you're taking part in a massive world wide event and helping raise awareness for Australia's Great Barrier Reef, one of the world's natural wonders.
Earth Hour is not about one hour in the dark. It's a symbolic act to get us thinking about our planet and our impact on it.
This years event will be aimed at highlight the problems with the Great Barrier Reef. There will be a special Reef documentary on Channel 10 at 6pm. It will be a great lead up to Earth Hour and will make the event more poignant.
You can host your own Earth Hour event. If you register your details and let the Earth Hour organisers know how you'll be celebrating Earth Hour, you could go into the running to win a fantastic prize.
50 of the most ingenious, the most fun, the most Earth aware events will win a ticket to "Camp Earth Hour" on the Great Barrier Reef! The prize includes snorkelling with turtles, a visit to a research station, meeting the climate change experts and so much more.
So don't waste any time, go to their website and register your event. It can be big or small, private or public. It's up to you.