Albert Michelson's harmonic analyzer — a 19th century mechanical calculator that can do Fourier analysis with just gears, springs and levers — was found at the University of Illinois, and then lovingly restored by a trio of makers who lavishly documented it in a book (free PDF/paperback/hardcover) and a mesmerizing video series.
Albert Michelson's Harmonic Analyzer [Youtube]
Albert Michelson's Harmonic Analyzer (book details) [Free PDF]
(via JWZ)