This isn't really a code but if you didn't know this already it is
good to know. After you learned a few spells like flipendo and the
spell that opens locked doors you can go through mirrors! When you are
playing a game and you see this really shiny mirror that has only your
reflection in it cast a spell on the mirror. Once you do that the
mirror will open or it will look really foggy, and cloudy in the room.
Go right up to it and climb in.. inside there are usually many things.
Sometimes a box with a chocolate frog, some with beans inside,
sometimes places that lead to wizard cards, and even to secret rooms!