By now everyone has probably heard replacing one just one regular light bulb with a compact florescent will save millions of dollars or make a take a nice chunk out of US energy consumption.

Hopefully you've kicked down a couple bucks for one of PG&E's discounted CFL bulbs and replaced a light or two in your place. If you haven't yet, Lights Out San Francisco has set aside Saturday, October 20th from 8-9pm as the hour to get to it locally and March 29 next year nation wide.

It's pretty simple: 1 night, 1 hour, 1 light bulb. They also ask you turn off non-essential lights along with City buildings and participating restaurants which will be holding candlelight dinners in a show of support.

Since this is San Francisco where we usually work a party into any good deed, we're all invited to watch the city go dark in Dolores Park where there will be music and free light bulbs.