Ever wanted to play around with an Enigma machine? Me too. However, they are few and far between, extremely fragile and very, very expensive.
I've set up this site as a bit of fun and education to show how these machines worked without having to vastly increase your home insurance.
In short, you can send someone (friend, family, sworn enemy) a message encyphered using a simulation of an Enigma M4, the German naval Enigma that gave the British codebreakers their greatest challenge.
The result will be encyphered identically as if you had used the real machine. In fact, you could use one to decrypt the message.
The recipient will receive the cyphertext by email with a link to come back to this site and attempt to decypher it. Don't worry, they will have a virtual Enigma machine, set up just like yours, to help them out.
Disclaimer: This is just for fun and is not affiliated with Bletchley Park.