Environmentalists: Prepare to turn out your lights. Plans for Earth Hour 2010 are officially underway — and the 60 minutes are expected to be darker than ever!

World Wildlife Fund’s Earth Hour is a now a 3-year-old annual event when everyone is encouraged to turn off their lights for an hour — saving some electric energy in the short term while hopefully encouraging all to ponder and act on environmental issues in the long term. In 2010, Earth Hour will be happening from 8:30 p.m.–9:30 p.m. on Saturday, March 27 — and according to the press release, is expected to be the “largest call for action on climate change in history.”

That’s because lights will be going out at iconic places around the world, from the Empire State Building to the Golden Gate Bridge to Mount Rushmore to big hotels on the Vegas Strip. Like last year, many cities — and even entire states — are expected to take part in the event as Earth Hour partners — and plan fun events for the hour of darkness. In Los Angeles last year, for example, we had a big event at L.A. Live featuring the mayor, a live D.J., and other performers. Many restaurants offered special candlelit Earth Hour deals, and comedy theaters featured half-lit performances.

You can find out if your state, city, town, business or organization has signed up to join Earth Hour by visiting the website and clicking on your state — then use Earth Hour’s toolkit to get all those groups involved. Of course, many individuals plan their own electricity-free activities, whether it’s a candlelight enviro-rally with friends or a solitary nap. Mark March 27 on your calendar and start planning now.

Get ready for Earth Hour 2010
On March 27, cities around the world will turn out their lights for 60 minutes.