Whether or not you read/saw the DaVinci Code, you have probably heard about the device in it called a Cryptex. The author, Dan Brown, coined the word and explained the concept. It works something like a combination lock, but his idea of vinegar dissolving the papyrus scroll inside does not work at all. Just the same the device fascinates a lot of people.
For more information about the cryptex in the movie, search on wikipedia for cryptex–it’s a pretty interesting article.
Here are directions for making a “crptex” that looks similar to the one in the movie. You might like to try making it for your own enjoyment and the amazement of your friends. Some people sell these, so you might be able to turn a hobby into a side business with this.
Click title for link to Instructables. Have fun!