Last night, Katie and I turned off all the lights and read by LED tealights for Earth Hour. This morning I did some estimates on how everybody did last night: Google Docs Spreadsheet
I have to say that the estimates are quite rough, based on 2005 estimates for personal energy use, and on press coverage versus population in various regions. The final line is based on the worldwide per person estimate from 2005, and on the WWF's estimate of 1 billion people participating.
I'm glad to say that we apparently saved between 3 and 30 GWh. Yes, that's Giga-Watt hours.