Myself, my husband, our son and niece are going to do this in December. The husband has desperately wanted to do this. So we will be 7 nights @ Universal Orlando on-site and one of those days we will spend at Discovery Cove. The kids don't know about the trip, just that we are going somewhere; the husband knows we are going to Universal, Kennedy Space Center and a couple other places, but knows nothing about DC. The plan is to wake them up early that morning, tell them to pack shorts and a bathing suit, hop in the car and head over. They are going to be SHOCKED, especially the husband.
Can't wait to finally experience this! It sounds absolutely wonderful.
We are surprising our kids also. First the surprise to go to Disney world for Christmas. While we are there we are going to surprise them with two days at universal and one day at Discovery cove. We won't even tell them about the dolphin swim until we get there. We are going in January. I'm hoping we don't have to cancel due to it being too cold. I think surprising your husband also will be so much fun.