If you do travel down Florida a bit and you think your kids might like that sort of thing, you might look into Butterfly World for a different sort of day.
Is a bit expensive, but the free guide books at the rest stops have some coupons to take the edge off.
We enjoyed it very much, besides just seeing the many types of butterflies, they do a great job of displaying educational info about them without making it feel school-like. Also, lots of crazy types of plants and flowers, plus a bird section where you can feed them, which our kids really loved.