One of my favorite "holiday" drinks is the Christmas Nui, created by Helena at A Mountain of Crushed Ice. It's a classic Don's Nui Nui formula with a couple of slight twists that steer it into Christmas flavor territory. The rum is punched up in flavor by substituting Smith & Cross and some Lemon Hart 151 in place of the original's gold Virgin Islands rum, and the Angostura bitters are traded for mole bitters (substitute Fee's Aztec Chocolate as needed; the results are still great). Otherwise the classic Nui Nui flavors are present: lime, orange, pimento, vanilla, and cinnamon. In fact, without too much altering, the Nui Nui is already hitting some traditional Christmas notes.
I mix these pretty often around Christmas and am just now realizing that the recipe is probably made for 2 servings - I'll have to try it that way. When made for 1, it's extremely potent, so make one at home, relax with some classic Christmas tunes from the 40s, and try to let the season wash over you.