Things I did for my first
Disney cruise:
1)Decorated pillow cases for each child with their favorite character. Turn these in in ziplock bags (along with a permanent marker)to the customer service desk (I forget what Disney calls it), and pick it up at the end of the cruise (or they will call you) and they will be all signed by the Disney charactors. I included a bag of candy bars for the characters. My grandkids are still sleeping on those pillow cases!
2)Pick up a picture frame mat from your craft store for a 5x7 or 8x10 photo. Pack it along with permanent markers in a ziplock bag and leave it with the customer service desk for the characters to sign. I included a bag of candy bars for the characters. When you get your pictures back you have an autographed matt to put around it for your own special memory!
3)I used graphics that I found on the internet to make custom autograph books for each child. I did not have pictures of my grandchildren with the characters (some people use those and they are so cute) but I had special pages for all the charactors that generally are on the cruise to give autographs! I used shutterfly to prepare and have the books printed. They were great. Hand made ones are really wonderful as well! I am not so good at that so I stick to the digital stuff!
4)Magnets. I became obsessed with magnets for the cabin door. I could not sleep, work or think about anything except magnets. I populated three cabin doors with personalized magnets. My family thought I had lost my mind!

I think I might have for a bit too! If you are interested you can go to:
http://www.disboards.com/showthread.php?t=2745821&page=37
and just read and read. I ordered magnets and used a cheap inkjet printer and cut them out myself and my magnets were wonderful!
5)And, don't forget the FE. I had an entire large size suitcase of stuff. I thought DH was going to murder me before we got it on the ship and it all passed out. It was so worth it. The most fun was letting the kids give the gifties out to other FE participants. They loved the giving...and then there was always a little something for them each day. I took a couple of surprise gifties for my grandkids, just in case our FE ended up empty for a day. But it never did!
There are so many great ideas for things to do by searching here on the disboards. Just take a look and you may see something that will make your trip fun and make a memory for later!
Anyone has any ideas to share, I would love to see them posted here!