If you want to build a Cryptex geocache similar to this, check out this video.
I visited Bloomington, Indiana and hung out with a great group of geocachers - MonsterCatAmbush, DJHobby, ErWin and Mickey4Jes. Bloomington is famous for being the home of Hoagy Carmichael and Indiana University.
The geocachers here are concerned about improving the quality of geocaches, and go to a lot of trouble to put out the highest quality hides. They were very hospitable and showed me some of the quality hides around town. They were kind enough to give their views on video, and I'll put them soon.
Here's an amazing geocache container called a Cryptex created by MonsterCatAmbush which will be used as part of a mystery geocache. It consists of an outer container made from three concentric tubes and an inner container. You can only remove the inner container by rotating rings that form a combination lock.
You can see that he has gone to a lot of trouble to put this together. He really knows how to geocache with high quality geocaches. Check out the video.