Hi Jenny,
Our family has been fortunate enough to visit Disney World a number of times also. While I can't ever say we became "bored" , we also looked for new things to enjoy to add an extra element to our trips.
The first thing we did was purchase a Hidden Mickey book and start on the Hidden Mickey search. These Hidden Mickeys, and sometimes Minnie's, Donald's and a few other pals, can be found in all of the theme parks and resorts, most restaraunts and other surprise locations. We love the challenge of finding new Mickeys each visit.
We have also become a Pin trading family. We each picked a couple of themes or characters we love and began to purchase, hunt and trade for every pin in our category. Besides having a great time, and some wonderful keepsakes. This is also a great way to teach my boys good communication skills. Another added bonus is the chance to interact with the Cast Members. Many Cast Members are a wealth of information and trivia about Disney World. We have learned the most amazing stories and hidden gems from Cast Members that are more than happy to chat.
We have also become big "watchers". Now that we have experienced most of the Disney attractions many times, we look beyond into the shadows. We love to look at the details on each prop or character or how the lights fade to add depth to a setting and so on. We still find new things and elements every time.
If you are interested in some behind the scenes peeks, you may want to schedule a tour or two. You can find information on the various tours and experiences
here.
Hope some of these ideas add some extra fun to your next Disney trip.