The Mythbusters gang built a gigantic code-wheel for a demo at the RSA conference and now they're auctioning it off, with proceeds to the Electronic Frontier Foundation:
What we have here is a genuine functioning coding cryptex built by Adam Savage and Jamie Hyneman from Mythbusters. They used it for a demonstration at the RSA Conference at Moscone Center in San Francisco, April 24th, 2009. See a video of the demonstration at the following link: http://media.omediaweb.com/rsa2009/keynote_catalog.htm.
The client wanted a unique demonstration of something to do with encryption and secrecy, and Jamie Hyneman, and Adam Savage designed, built and used this machine to encode the phrase "Cryptologists do it in secret". Then they went on stage at RSA and used the machine to DECRYPT the secret message. The appearance was a smash success. The crowd was great. The machine worked great.
THE MACHINE: at 13' long, and just over 6' high, it's made to be highly visible, even from the back of the audience. It's composed of a long pole, holding 29 distinct wheels, built from MDF and Cintra, with applied vinyl letters. There are 4 different alphabet wheels randomly distributed among the 29, making this a moderately robust coding machine (save for the fact that pictures here compromise it's secrecy). All of this sits on a custom welded steel frame and heavy-duty castors. Although it weighs approximately 300 pounds, it rolls around quite easily.