On the night before the night before Christmas, in Oaxaca in Mexico, there's an exhibition of radish sculptures known, obviously, as The Night of the Radishes. Not sculptures of radishes, which would be quite boring, but sculptures made from radishes, which also sounds quite boring. This is definitely a festival we could enjoy here, as it would boost the fortunes of radish farmers and keep salads mercifully free of the little pepper grenades. Plus radishes are raphanus sativus, and if there's something Kiwis excel at, it's cultivating sativas.
Shoe throwing
In the Czech Republic, it's traditional for unmarriedwomen to stand with their backs to the front door and throw a shoe over their shoulder. If it lands pointing towards the door, she'll be married in the coming year. While it's unwise to blindly biffshoes around in a room full of people after sampling Cousin Sarah's homemade, we could adapt this tradition, replacing shoes with Jandals and throwing them at the front door until any visitors bringing presents after you specifically said "let's not do presents this year" have gone away.
Carolling
Going house to house with an acapella group doing Christmas carols sounds more like a form of terrorism than a celebration. We have a version of this already: the Salvation Army brass band on the back of a truck pumping out Yuletide hits until we give them money to go and share Christmas joy with the neighbours. But if we translate carols into a language we can all relate to, we could really get behind it: God Rest Ye Merry, Gentlemen becomes Chillax, Bros. Frosty the Snowman becomes Frosty the Beer Can. Good times.
Rollerskating
Rollerskates were popular requests in letters to Santa until the 90s, when rollerblades killed the joy of wheeled feet. In Venezuela it's traditional to make your way to Christmas mass on rollerskates, which is an adrenalin sport Kiwis could get behind, particularly after a few wines. While rollerskates would be frowned on at actual church, we could make this tradition our own by travelling to Christmas In The Park by skateboard and heelie shoes, maybe doing some festive tagging on the way.
Mari Lwyd
A Welsh tradition in which a mare's skullis affixed to a pole with cloth and ribbon. In the persona of Mari Lwyd, it goes around visiting people, asking for beer and food for the accompanying men. This takes it a bit far. The only skulling at a Kiwi Christmas involves the contents of the chillybin, and an animal on a stick is called a spitroast. Mare-y Christmas everyone!