From the MAKE Flickr Pool:
OverWired designed and built this PC-based jukebox using arcade button switches and a KeyWiz keyboard controller.
More KeyWiz info from RetroBlast:
The KeyWiz Max 1.5, by Groovy Game Gear, is a PS/2 keyboard encoder for MAME controller applications. It’s a compact 32-input encoder unit, with a “Shazaaam!” shift function to double the number of effective inputs.
overWired’s jukebox on Flickr – Link
KeyWiz on Retroblast – Link
Homemade touch-screen jukebox – Link
“iTunes” jukebox – a physical playlist device – Link