If you have a computer that you happen to leave on a lot when you aren't using it, check out this article about using "S3" Standby. It's for Windows, but there is probably something similar for Macs out there. Though, I wouldn't be surprised if they do it by default. It's a little bit tech heavy, so if you aren't up for it, buy some whiskey for you geek friend and get them to set it up for ya. The example cost listed in the article is about $35/month for an always on computer. Now most folks won't have machines that take up quite that much juice, but you can probably save at least a few bucks.