For many of us, our computer is a necessary part of doing business. According to the Environmental Protection Agency, if every computer in the United States were switched to an Energy Star-approved model, we'd recoup about $1 billion in annual energy savings in just one year (and reduce greenhouse gas emission by 15 billion pounds). When shopping for new computer equipment, look for the Energy Star logo on desktops, laptops and small-scale servers to find the most energy-efficient models. Learn more at energystar.gov.

Would you believe the biggest killer of birds in the United States -- 1.3 billion feathered friends per year -- are cats? If you have a pet cat and can't keep it inside, be sure to add a bell to its collar. Since cats have the ability to stalk their prey and pounce, a small bell can make just enough noise to give warning to the birds (and other small animals) that they're in harm's way. You can find other collars designed to prevent cats from harming birds, but a simple bell works just fine.

If your car is parked and idling for more than 10 seconds, turn it off. Even though you're not driving at highway speeds, a car that's on but not moving is still using one-quarter to one-half a gallon of gasoline per hour. In the colder winter months, if you want to warm up your car, it's recommended you do it for no more than 30 seconds total. With new models, that's not even necessary; it's driving that actually warms up the engine, not simply turning it on.