Being Danish living in the UK, I am actually quite lucky that I get more holidays to celebrate as Denmark and the UK don't have all the same holidays, but I quite often forget. For instance in Denmark we have a day where we eat duck/goose, called Saint Mortens eve and a day where we eat a bun/roll called a Hvede, called big Hvede day.
Where as here in England there is pancake day, St. George day and Halloween.
The Danes have however started taking on Halloween, though it wasn't around when I was young. We do have another very old traditional holiday where kids dress up, called Fastelavn, normally celebrated around February. Going back to the origin of this holiday, it was to celebrate the beginning of the fast, that would then end with easter celebrations.