In England, on November 5th, we mark the foiling of the Gunpowder Plot of 1605 by having a large bonfire and burning an effigy of Guy Fawkes. There are lots of fireworks and generally merriment. - Simon

It's also where the word "guy" comes from. The event led to the use of the word "guy" as a term for any "person of grotesque appearance" and then to a general reference for a man. - Simon