Pretty lame, but I had a lot of fun.
I also made a font for kids who like codes. You type them a message, then switch it to this font. It rotates all the letters with others in the alphabet. A becomes J, B becomes K, etc.
Download it here, drag it into your Fonts folder, then use it in Word (or whatever) like any other font.
http://2ttf.com/7rwREJZpL6 . I scrawled the whole set in 5 minutes this morning, so it’s ugly, but I doubt your kids will care. Try it! That would make me happy.