Varies by resort. Checkout Youtube. You will find many of these special events documented either by Couples or by the people who have stayed there. For the most part, Couples will have something special going on for the holidays.
I am seeking information about all resort activities on December 31st and Jan. 1st, clothed or au natural. In Ohio, we have an annual morning swim in Lake Erie, regardless of the weather. Didn't low if there were any unique island traditions to partake in.