Oh now i see Larry... I suppose that Thanksgiving is what we call here "Acción de Gracias". We dont have such day here, but they translate it like this on films
. Anyway, people here doesnt amke gifts on 24th December (Santa Claus), but on 5th January (called here "The Magic Kings", in spanish "Los Reyes Magos"), so busiest days are probably from 2nd to 4th of January, though there isnt a specific day that could be called the BUSIEST of the year.