A green thing you can buy for the holidays that is also useful: an LED lamp.
LEDs use much less energy than even compact fluorescent bulbs and last almost indefinitely.
In Copenhagen, futurists are pushing LEDs for the developing world. They can cut emissions by replacing kerosene light, in combination with solar panels and batteries--leapfrogging the traditional bulb or compace fluorescent. And they are more durable.
I got a Z-Bar lamp with five small LEDs that generate plenty of light with just 9 watts. The light is clear and white, by contrast to my older Ikea incandescent in the same spot They leave five shadows, too, so I feel vaguely as if I am on a sci fi planet with multiple suns or moons.