When I was a kid we lived in a neighborhood that was built by the same builder for most of the houses. They all had the old school intercom systems inside so you could spy on people in other rooms and call people to the door without having to yell or run down the hall. It was cool, but now that technology has progressed if you have one of these old intercom system is your home it might be more of an eyesore than something useful.
A company called Intrasonic has announced a new system that will allow you to take any old home intercom system that uses three wires and upgrade that system to be used as a whole home audio player. The system is called the Retro-M and it comes in white, almond, and black colors. The device allows you to choose between two sources with a MP3 player connector for your iPod and a radio source for music off the air.
It also upgrades that old intercom system with a new one that allows you to make selective calls for privacy. The intercom will blast the whole home at first but once the person answers, it is private. It will work with any player that has a 3.5mm headphone plug. It can be expanded to cover 13 zones, two doors, and has a single aux input. The only downside is that the system isn't cheap at $1643 to fit five rooms, one outdoor location, and a single door.