Want a fun trip for an all-day non-Disney activity? Road trip to Caladesi Island.
It's about a two hour drive to the Gulf Coast, just north of Tampa/St. Pete.
You have to then park the car and take a ferry to the island. Once there, you have the beach to yourselves and maybe 40 other people. You can rent an umbrella and chair on the beach. The water is warm and full over seashells for the kids. There are nature trails. Showers. A snack shack and gift shop. All the comforts of a developed beach, but all the flavor of a deserted island.
After four hours, you catch a ferry back, tired but happy. With drive and all, its an 8-9 adventure. Oh, and Caladesi Island was just named the #2 beach in the United States according to something I saw on Yahoo last week.
('course, if I was in a seminar, I'd want them to wait until I could go, too)