Weird Question: How do you make a mash-up?

[elfs]

Don't ask how this happend, but by accident I started feeding both the soundtrack to Kannaduki No Miko to the soundserver but had neglected to turn off XMMS, which at the time was playing Moby's Everloving.

Frighteningly enough, they worked. Now I have to track down which track I was listening to and figure out if I was just hearing things or if I have something worth exploring further.