A classic hand-encryption system, "Solitair", was designed by Bruce Schneier for Bruce Sterling'sNeal Stephenson's book Cryptonomicon. It uses identically shuffled decks of cards, one per communicating party, to encrypt text. According to Bruce (who is perhaps not a disinterested party), it is a very strong cipher.
Unfortunately, there's no way to revoke someone's access to the cipher (unless you sneak into their bunker and re-shuffle their copy of the deck).