Hey, tonight is Earth Hour! I almost forgot!
At 8:30 local time tonight, turn off your lights for an hour. Not all of them, just the ones you aren't using. Shut down the appliances, too. Don't leave the TV on, don't set up the automatic coffeepot for tomorrow (leaving ground beans in a coffeemaker for that long oxidizes them and makes them bitter anyway), whatever. You know your place better than I do, so poke around and find things to unplug.
It also helps to turn off outside lights, too. Take this chance to go outside if you can and look at some stars! Saturn is up now at sunset, hanging under Leo's belly. Orion is up, too, and Sirius, the brightest star in the night sky. Maybe you'll see the newly upgraded space station!
I think this is a good idea. It's not a big deal, and won't save the world... but it might make you aware of the stuff you leave on all the time. Now, if I can just get my teenaged daughter to shut off lights ever... and you kids GET OFF MY LAWN!