Light-emitting diodes (LEDs) are almost the perfect artificial light source: They last a long time (50,000 hours), are very shock resistant, don't produce much heat and are very energy efficient. The "almost" part is because they are still relatively expensive (that can be solved) and, until now, didn't produce a very appealing light-color. Originally, they only produced red, yellow and green light. Then came the blue LEDs which were made to produce more or less white light, but anyone with a LED-flashlight on his cellphone knows that it's still very blue-ish. But all of this could change thanks to an accidental invention by Michael Bowers, a graduate student at Vanderbilt University. He was trying to make quantum dots when he discovered a way to make LEDs produce white light. "I was surprised when a white glow covered the table," Bowers said. "The quantum dots were supposed to emit blue light, but instead they were giving off a beautiful white glow."
The Department of Energy estimates LED lighting could reduce U.S. energy consumption for lighting by 29 percent by 2025.
Thanks to thanks Ben Clemens for the tip.
Update: Jamais at Worldchanging has a good post about this.