Hi,
The FE exchange is fun, it involves hanging something like a small shoe bag, but much smaller with pockets from the fish that hangs outside of your cabin where the cabin number is located. Basically extending below the fish. I will try and find a picture of mine from last year. If you sew you can make one, but there are people on the DIS Boards who make them in whatever color you like with Mickey patches on them and personalized if you like. You have a list of people and who are participating and you bring an item or items like candy, postcards from home, penicls, custom magnets commemorating the cruise, you can lable the bag or item with your family's name and where you live, and you put them in a bag and deliver them to each fish extender during the cruise. We had fun with this, finding them. There is a list of participants and where they are located on the ship. You can make one bag for each cabin or for each member of that family. The kids loved finding surprises almost every day.
This is the lady who I ordered a custom FE from. She did a great job. The picture wouldn't add so visit Ebay and if you look up Fish Extenders, we used the seller gradysmommy.