I thought this was pretty cool: a hand-cranked machine that plays pretty good music. Made by Swedish band (or just one of the band members?) Wintergatan, It took 14 months to build. I was a little skeptical about the authenticity of it, but I watched some of his other videos showing how he built it and how he did the sound. It is quite an amazing job!
Article & YouTube video:
How it works (part 1):