The Wildcat Chronicles:
"Skylights are a great addition to any house, as they bring in more natural light – cutting down on artificial light electricity costs, as well as promoting good health for a home’s occupants. Unfortunately, however, skylights are hard to install in most pre-built homes because they require so much roof real estate. Also, unless the sun is at the right angle and there are absolutely no clouds in the sky, skylights don’t always illuminate a space in a way that makes their cost worthwhile. Thats why we love Solatube – a smart technology which takes skylights one step further by refracting, reflecting and concentrating solar light into a small tube using mirrors and lenses." - Above quote from http://inhabitat.com/solar-tube/
BTW, most of our buildings here on the homestead employ a very simple solar light device: A flat piece of translucent fiberglass that is interleaved into a roof covered in asphalt shinglers. Ultra simple, it lights up the room(s). Has worked well for 40 years.