Cheap Acoustic Guitar Pickup
I love this: it’s cheap, effective and pretty simple to do. Basically, you take a 2$ Radio Shack piezoelectric transducer and use it as pickup. One thing bothers me a bit though: you need to drill a hole in the guitar to fit the jack. I’m quite sure there’s a way to go around this. And who cares, I don’t have a guitar ;)
I might build an acoustic bass out of scrap wood I have at home, and that sort of pickup would be perfect for it.