An easy option that is very much in the Christmas spirit. Make as a large punch bowl, or just for one.  

One part lime juice
Two parts sugar syrup
Three parts Rum
Four parts soda water
Dash of bitters
A sprinkle of nutmeg
Seed + Stow Dried Lime Slice

1. Mix all ingredients over ice
2. Garnish with a Seed + Stow Dried Lime Slice.