The "some sort of aquarium" is VERY good. Also not cheap. Well worth the visit if you like such things, but Maui in 2-3 hours? I seem to remember my research suggesting some sightseeing to do (adj. to the AP) within a few minutes of the airport, or a more time consuming walk.

Probably the best thing would be to load up your family in a car and make a hour away/hour back run and have a bite to eat.