I figured this hack was in the works for some time now, just happened to run across it this morning.  Thanks to Firefox, Greasemonkey and a little creativity from a scripter out there you can download music from the MuxTape web site.  Here are the words of wisdom from the script creator…
This downloads muxtape songs. Just click the “Download me!” link, change the file-name to your liking and append .mp3 to it.
There you go!  Pick up the Greasemonkey script [...]