Less Addisoncentric, more Maddek friendship. Because hey, they sounded like fun before Seattle came along.
Christmas
"'Twas the night," she says dryly. She's curled up next to Derek, throwing popcorn at the fireplace.
"Before Christmas," Derek continues.
"When all through the house."
"Not a creature was stirring."
"Not even a..." The pair wait a few seconds, before Addison leans forward and slaps Mark's head.
"A mouse," he says, irritated. "Every year. What kind of weird mind games are you trying to play?"
Reference: 'Twas the Night is a poem by Clement Clarke Moore, which basically established the names of Santa's reindeer. Why Addison and Derek make Mark say "a mouse" every year, I don't know, but it sounds like a silly tradition that they would indulge in.