In my novel Get Happy, Minerva makes a fake uke out of a cookie tin and a ruler so that she can practice learning her chords. People do make home-made instruments–some that you can actually play. Jilleen Moore makes all kinds of guitars (like the one to the left) and stringed things out of treasures and stuff she finds. You can see more on her Facebook page.
My friend Bill Williams is making “canjo-leles” and more. His peanut can pictured here is my fave. You can find out more about how to make your own in this book by David Sutton.