< Coaxial, the ancient wonder tech
As wonderful as coax is, I was nonetheless happier when taut kite string between paper cups ruled my communication world.
Signal-over-Acoustic-Resonant-Wire (or SOAR for short) (trademark pending). I wonder if it's possible to wire up a house with taught strings, and have exit points in every room. That way kids could hear the movement of the spiders in the walls, complemented by the background sound of their parents copulating in the night, and I think that's truly wonderful.
<sips coffee thoughtfully>