A couple of things come to mind:
They have tennis courts, a pool, a mini-golf course, and I believe shuffleboard all at the resort...
the resort is direct on the ocean so there is plenty of space to walk there.
then, they are also close to the jungle trail and pelican island national wildlife refuge which they could either walk to, or more likely drive to.
DVB I believe also has bicycle rentals available for them to rent.
The Green Cabin Room hosts a drink seminar daily - I believe it is on a 3 or 4 day rotation of the classes. They also host some sort of a trivia game every day at 5:30 PM.
Recently they announced some pirate character meet and greets will occur every Thursday, but I don't think that is a permanent addition - just for the summer. There ARE character breakfasts every Saturday morning.
Lastly, Wind & Waves offers sit down service for Breakfast every morning and dinner every evening. DOn't know if it makes sense to eat there every night, but it is an enjoyable place to be there.