Definitely go on a nickelodeon cruise ship or disney world. You'll probably also enjoy it a lot. They make those kind of things pretty sweet for adults as well as kids.
SEAWORLD....we took my son there when he was 18 months old and he had so much fun. He is an animal lover and just was sooooo happy! If you buy a days pass you can get it stamped and use the pass for the whole year so....we went everyday we were in florida it didn't "get old" some days we went in the morning...sometimes after dinner. stayed a mile away in a child friendly hotel, nice pool, playground. We went back just as the expiration was ending so just less than a year...saved us $200 because we didn't have to pay to get in again. It was $70 7 years ago to get in. We have gone back 5 times and we all love it.
they tire easy at this age.. so think in terms of not a full day .. they will get cranky and crying before you are ready to quit...I am thinking a day at a zoo would be cool
Anywhere on the gulf where it is warm, kids love the water. BTW, don't go to Disney world, it is way overrated, the lines are ridiculous, and your son would probably honestly be miserable the whole time.