The Solatube is a great way to bring natural light into a room, in a totally eco friendly manner. They work thanks to LITD:

Solatubes innovative technology makes it possible to capture a maximum amount of sunlight. The Light Intercepting Transfer Device (LITD®) increases the surface area available to intercept direction sunlight no in the direct path of the tube opening, then transfers the light down the tubing. The result is increased light input and increased light output. The Spectralight(R_ Infinity proprietary super-reflective tubing has the highest reflectivity in the world for the brightest purest light. It provides near-perfect color rendition. The Raybender® Technology intercepts light that is not in the direct path of the tube and redirects it down the tube at a steeper angle, minimizing reflection loses

Available from the Enviromental Home Center, with prices starting at $300. [Found via Crib Candy]