I LOVE this "Litre of Light" project in Manila.
Basically, they take a litre-sized soda bottle, fill it with water and bleach (to keep algae from forming), and shove it through a hole in the ceiling. Unlike just putting a hole in the roof, which would admit light in a straight line, the water in the bottle refracts the light, and it really does look like a light bulb in the ceiling ... but it's just sunlight streaming through a water-filled soda bottle.
According to a tech-y guy on the Portland Permaculture forum, this same technology could be used even here in Maine, if the bottles are filled with an anti-freeze solution (like isopropyl alcohol or vodka :).
In the parts of in my house where I could use the most light, I have a crawlspace/attic space, and so a soda bottle wouldn't work, but how about using this technology in the walls instead - to bring light from a bright room into a dark room?
Definitely something to think about.