One of my favorite FREE things to do at Walt Disney World is "resort hop." The Monorail Resort Loop is my top choice to 'hop.' It's easy to get on the Monorail and ride to the Contemporary (with Bay Lake Towers), the Polynesian and Grand Floridian Resorts. Get off at each stop, browse the lobby, gift shops, restaurant options, and pool/ outside areas. It's amazing how all the resorts have such a unique feel.
Another easy area to 'hop' is the Crescent Lake Resorts between Epcot and Hollywood Studios. You can walk around the lake, or take the Friendship Boats, to visit the Yacht & Beach Clubs, the Boardwalk, and The Swan & Dolphin Resorts.
If you are staying on WDW property and have your own transportation, you can drive to different resorts to visit. Having the parking pass for your resort will allow you inside the other resort parking areas. Tell the attendant what you are doing prior to parking.
Which resort is your favorite to visit?