For £19.95, this site will sell you a kit to build a working organ made out of paper, with 8 pipes and a punched-paper sequencer. This page explains how it works, and this page has big colour pictures of the pages before they've been assembled. By way of tribute, MT reader Tim writes: "I've found the following free
download+printable paper instruments in order of decreasing playability: Ocarina (i tried this one a while ago, works pretty well!), Japanese Paper Drum Kit, and Acoustic Guitar. Time to start a paper band!"