actually, I want to use my computer as a jukebox to play songs around my house. But, at the same time, I still want to be able to watch videos and surf the internet without everyone in the house having the music interrupted by crazy web game audio.
My computer has 6 audio out jacks which you can program using Realtek to perform any of the various audio channels (sub, front, rear, mic, etc...) so it just seams natural that I could use those to play separate audio out sound.
Anyway, I recently heard of this device that you can use to mix audio, sort of like a DJ. It has a separate audio out port that plays a preview (something like 1 min ahead) of what will come out of the other audio jack. That way you can make sure that what you are mixing sounds decent before everyone else hears it. That is what gave me the idea.