I have to admit that it is mostly symbolic, but being plunged into darkness for a time can be both exciting and discombobulating. Does it defeat the object of the exercise if I sit and listen to my wind-up radio? Will I just sit and read by candlelight? Or will I take a leaf out of other's books and go for a walk to see which of Edinburgh's landmarks has participated.
Actually, given that I'm used to traversing Princes Street in the wee small hours to and from work, I'm well used to seeing the Castle in darkness - but will the city fathers be turning out the lights on Calton Hill or The Mound?
Here's the official, "inspiring" video for this year's Earth Hour, followed by a slightly more tongue-in-cheek one from Green Thing:
(As usual with videos, if you're reading this via email or some RSS readers then you may have to visit the site to see them)