I went to
Paradise Beach last time I was there. About a $13 cab ride from the International Cruise Pier. There is no entry fee, as their impressions are you'll spend money while you're there. Lounge chairs are $2, and use of their aqua park and snorkel equipment is $12. I'm not sure if they're open on Christmas, however.
__________________
2007 - Majesty of the Seas
2009 - Enchantment of the Seas
2010 - Freedom of the Seas