Nycblackout Don't be alarmed tomorrow evening if the lights in your city are suddenly a lot dimmer. More than 2,000 cities across the globe will be turning off lights to observe "Earth Hour." It's a worldwide event in which you're supposed to turn off your lights for one hour beginning at 8:30 p.m. in your local time zone.

Lights are scheduled to go out at hundreds of popular tourist landmarks and buildings worldwide, including New York, London, Paris, Dubai, Hong Kong, Moscow and Nairobi.

Organized by the World Wildlife Fund and supported by a host of powerful names -- from celebrities Kevin Bacon and Donny and Marie Osmond to global figures Archbishop Desmond Tutu and United Nations Secretary-General Ban Ki-moon -- the rolling electric turnoff will take place from 8:30 to 9:30 p.m. local time, beginning in Fiji and following time zones around the globe.

The idea came about two years ago in Sydney, Australia, when more than 2.2 million people turned out their lights at the same time. Last year, lights were flicked off in about 400 cities.

According to organizers, switching off the lights like this is a "vote" against climate change. That's great, but I'm mostly excited by the thought of the nifty Google Earth photos that will result (although things probably won't get quite as dim as they did in this photo of the New York City blackout in 2003).