I believe I'll dust my broom (and this time I'm going to use a real broom)
It's only got one string, it's called a diddley bow, and according to this site it's supposedly the origin of blues guitar playing. [Link via J-Walk.]
Rather than buy a diddley bow from the site I linked to above, or build one, I decided to improvise. I have a ramshackle El Cheapo brand electric guitar in my closet, so I losened the strings and stuck an Altoids tin in between the pickups. I was surprised at how much this small tin box resonated. I noodled around with a slide for a bit, but tossed it aside in favor of just fretting notes. The sound it produced at first reminded me of some West African instruments I've heard, but after I played around with it a little more I decided it sounded more like an oud. I'm curious to know what this contraption sounds like hooked up to an amp, but I pawned mine years ago and never got another one because I have the musical abilities of a donkey with influenza. Anyway, it was something to break the tedium of existence for a few minutes.