If you have an old set of computer speakers anywhere, they might have used that dual-end cord.
(1 Speaker plugs into the computer, then the second speaker plugs into the first).
My dad had a boatload of them where he worked (speakers getting thrown away), and he brought a couple home for me to use. One is on my computer, the other I use for the Aux In on my car stereo (I can plug my PDA in).