The electronics magazine "Nuts and Volts", http://www.nutsvolts.com/ ,
occasionally prints MIDI do-it-yourself projects.  In the October 2000
issue there is the ultimate MIDI project in the robot column:
a MIDI-controlled xylophone!  The construction article even goes into
the details of winding the solenoids.  More information and the Pic
controller code can be found at

  http://www2.netdoor.com/~rlang/xylotron/xylotron.htm

Julie Porter