After months in development, Philips is finally ready to sell LED light bulbs that last 20 years. Could be quite a game-changer — after all, if you didn't have to change a light bulb between now and when your unborn child graduates from high school, just think of all the precious minutes you could spend on other tasks. And the environment would surely thank you. Philips put the $60-bulb on sale yesterday, which was also Earth Day, of course. The bulb uses LED — otherwise known as light-emitting diodes — to light things up, instead of filaments, reports BBC News.