Here's a fast hack to extend your Xbox 360 cord.
Step 1: The Cord
I had this old USB cord that had a wireless WiFi adapter at the end. So I took that of and thought it would be cool to have a longer Xbox cord because it always came unplugged when I played. It's super easy to do and if you wanted to you could just keep adding USB cables.
Step 2: That's It
It works 100% and is easy to do.