I would like to second suggesting Kool Runnings waterpark, they have some neat rides, no long lines, very observant and on the ball lifeguards too.

I also highly recommend the Saturday show at Seastar, which includes a buffet dinner that has some great authentic jamaican dishes along and the entertainment is fantastic, the drummers are unbelievably good and if you want to you can check out the live webcasts on Saturday to see for yourself at realnegril.com