Are you Crypto Cat or Decipher Dog?
Me, I want to grow up to become CSS Sam.
What am I talking about? This site, of course.
Funny, it may be, as a concept, but if your kids show any interest in codes or ciphers (and I did when I was, ooh, seven), there's a lot of fun to be had at the "Games" section. Build your own cipher machines - yay!