Own a piece of music history
Wow, you really can find almost anything on ebay. There's an auction going on for a one-of-a-kind, prototype vocoder built for Kraftwerk in the 1970s (I assume- maybe it was built earlier than that) and used on a couple of their songs, including "Autobahn." Don't miss the great pics down below the description.
(Kudos to Jeremy for finding this... he said he didn't have time to post it, so I did!)