Check out JoyTunes.
http://www.joytunes.com/play

Awesome for recorder players and like to play games - this is a computer game that is controlled by live, regular recorder ! Kids play the games but actually practice their instrument. Teachers have free resources - sheet music, playbacks, progress reports, etc.
(Teachers version at http://www.joytunes.com/teachers.php?tok=edu )

perfect for elementary school kids.