Nyctography: A substituton cypher by Lewis Carroll

I learned the Daedric letters from the physical map that came with the game, which had the place names in both Daedric script and English.

I learned the pig pen cipher from a library book in maybe 4th grade. My friends had fun with if off and on through high school.

Those are the ones that I learned, from the magic system in Ultima Underworld. I think that H and W are swapped, and that Tolkien's alphabet includes a few more letters. They're both similar to the Elder Futhark runes, if I'm remembering correctly.

As a child I made several crypto disks out of cardboard, draw a 3 inch circle, give it enough segments to fit your alphabet, 32 is easy and gives you room for the capitals and some punctuation, draw the letters twice on each segment inside and outside of the circle, then cut out the circle, glue the outer part to a backing sheet and glue a tab/handle to the inner part to make it easy to spin.

Used statically it works as a simple ceaser cipher, but the real advanced ciphers became available if you rotated it by a specific amount after each letter.

Many plans and conspiracies about what we were going to do with our new "unbreakable" encryption system, but in retrospect, never used and more fun to build and think about than operate.