Turn off the lights! And the PCs, and printers, and the ...

Here's a thought. If your office is shutting down for a four-day holiday weekend, you can bring a little extra cheer to your boss by remember to shut off all the equipment that will be sucking up power when you're not there.

According to 1E, which makes power management software, "always-on" computers will cost companies and individuals upwards of $21 million over the holiday weekend. They'll also contribute an estimated 178,000 tons of carbon dioxide, or the equivalent of emissions from 32,000 cars.

Here's a little game to illustrate what to do.

In all seriousness, I spoke with Sun's vice president of eco-responsibility, Dave Douglas, earlier this week, and a total office shutdown is also being advocated by the tech giant, which will close down entirely for the work week between Christmas Eve and New Year's Day. Last year, the company saves roughly $108,000 by reminding its employees to do this, Douglas reports.

Have at it!