We actually turn off everything for the whole evening. We sit around as a family and just talk for a few hours. If it's cool, we'll have the wood burning stove burning and have some soup. If not, we'll eat earlier, then when it gets dark, just not turn on the lights. Everything but the fridge and freezers are turned off. We actually do this several times a year, but always make sure to mark Earth Hour.
Life is too short to eat processed, artificially-colored, chemically-preserved, genetically-modified food. Or maybe that IS why life's too short.