Aleph, from monome: Programmable Sound Computer That Does Anything (createdigitalmusic.com)

Official product page here[0], additional details here[1], and forum discussion over here[2].

This is very exciting. As with other monome projects, the hardware itself isn't open source, but everything else about the project is.

[0]http://monome.org/aleph/ [1]http://monome.org/aleph-details/ [2]http://monome.org/community/discussion/16777/