Christmas mainstays…

Summon the creature “Santa Claus”. He is an NPC that gives out a snowman that spawns snowballs about every 24 hours (might be 18, I don't know for sure).

To spawn a Christmas light pillar on a tile:

#xmaslight

To despawn Christmas light pillar on a tile:

NOTE: This command doesn't seem to work on Mythmoor, or it is delayed until the year's end. See below bullet point.

#noxmas

• All julbords disappear at the end of the year.
  
• Christmas ends at 11am on 12/31.
  
• The Christmas light pillar disappears at this time.
  
• The julbords pop a short time later, around noon or one.