In the book -the Da Vinci Code- a cryptex plays an important role. The cryptex is a cylinder with an important document in it, protected by a code word which can be
...Plus set by turning rings around the cylinder. This thing contains the files to print the parts which make a fully functional cryptex which can be printed on a 3D printer.
Three other cryptex designs are on thingiverse: http://www.thingiverse.com/thing:1751, http://www.thingiverse.com/thing:2695, http://www.thingiverse.com/thing:2708, but this design was started independently based on ideas found in instructables.com. The other thingiverse designs do not contain pictures and seem to have some design issues which probably means they were not completely finished.
A short video showing this cryptex in operation can be found on youtube: http://www.youtube.com/watch?v=BjUNWvj0Q68
The printer used is my repstrap printer which is documented in the blog: http://pasutx.blogspot.com
