Plasma Lightbulb
Silicon Valley company Luxim has created the most efficient light source yet, at 140 lumens (units of light output) per watt. For comparison, today's most efficient LEDs only produce 70 lumens per watt, and a normal incandescent bulb produces a measly 15. They have produced a bulb the size of a Tic Tac that produces as much light as a street lamp using a fraction of the power. They use an electrical charge tightly focused into a small capsule of argon gas. The argon turns into a 6000 degree plasma, as hot as the surface of the sun - which is the reason why the light it emits has the same spectrum as natural sunlight. Check out the CNET video to see it in action.