Researchers at MIT have demonstrated a new kind of incandescent light bulb which uses nanocrystal structures surrounding the filament to bounce heat back and re-emit the energy as light.  The new technology would allow incandescent light bulbs to be more efficient and cheaper than LEDs and compact fluorescent bulbs, while at the same time eliminating the need for toxic materials and bringing back faithful color rendering to boot.  Very cool.  Check out MIT News for the details.