What happens when they gather on Jan. 25 and toast the lump of offal that jokesters love to mock — You haven’t lived until you’ve seen a kilted Scot try to keep a straight face as he rhapsodizes about a fat haggis on a silver platter, especially if he’s had a wee dram of Glenfiddich. That’s a highlight of the annual celebrations worldwide on the Jan. 25 birthday of Robert…