I have CAT5 running all over my house (inside the walls), but it goes unused most of the time. So instead of using it for computery stuff once a year, I’ve decided to simply run stereo analog audio across it from room to room. The wiring is there, why not use it? A couple of audio baluns is all I need and I’m up and running.

CCTV Video Audio Power Balun BNC Via Cat.5 Transceiver
Audio balun
$3.67 - CCTV Video Audio Power Balun BNC Via Cat.5 Transceiver
Component Video,Digital Coax Audio Cat-5 Balun Extender
Audio balun
$69.50 - Component Video,Digital Coax Audio Cat-5 Balun Extender
Camera Video audio Power Balun UTP CCTV Transceiver
Audio balun
$9.59 - Camera Video audio Power Balun UTP CCTV Transceiver
Related posts: Ultra cheap USB audio adaptersOlympus VN-4100PC