part goddess, part mountain goat
This page explains simple cypher tools and gives examples of each where you can try them for yourself and see the results. Easy and accessible, and like a no frills game to explore. Helps (me) in understanding the encryption programs on offer out there.
From the page: "Let's say that you need to send your friend a message, but you don't want another person to know what it is. You can use a full-blown encryption tool, such as PGP. If the message isn't that important or if it is intended to be decrypted by hand, you should use a simpler tool. This is a page dedicated to simple text manipulation tools."