“Deck the halls with boughs of holly, fa la la la la, la la la la…” Nick sang various Christmas songs to himself as he decorated the conference room for his private Christmas/Hearth’s Warming crossover party later that week between him and his friends. There was a tree all decorated and tinsel hung from the ceiling, along with figurines of major Hearth's Warming figures and plenty of hot cocoa supplies.
Suddenly, there was a knock at the door. “Who's there? Actually, just come on in. I'm just setting up in here.” the door swung open, and the ponies behind it stepped through. Nick's attitude immediately perked up. “Oh! Celly, Luna! What are you two doing over here? Not that I'm not happy to see you two, of course.”
Luna spoke up first. “It is always a pleasure to see thee, fair Nicholas. But We have come to, unfortunately, deliver a complaint.”
Nick looked at his friends in shock. “A complaint? What for? I'm not breaking any fire codes, am I?” he glanced around the room, trying to figure out why the royal sisters would complain to him.
“Actually, we aren't the ones complaining,” Celestia explained. “A certain noble pony has asked that we, and I quote, ‘Tell that filthy ape to stop his caterwauling so that I can enjoy my dinner in peace!’ He then added that ‘There's no way in Tartarus he could be any more loud and annoying!’”
Nick pondered for a minute. Clearly Blueblood was being a bigger jerk than normal today. “Is that an actual warning, Celly?”
The solar alicorn grinned. “I prefer to think of it as a challenge. Need some help?”
“Oh, certainly! The more the merrier,” Nick added with an evil grin.
It took a good hour and a half to gather the supplies needed for what Nick referred to as ‘The most loudest war of loud that ever was’, but a few trips to the storeroom ended up being fruitful in ways the three pranksters didn't expect.
“For the record, whatever happens, this is awesome.” Nick ran around making sure all the equipment had the energy crystals properly attached.
“We are ready. Art thou ready, sister?” Luna stood with a guitar in her magic, wearing neon sunglasses and a backwards camo baseball cap in place of her crown.
“I'm good to go.” Celestia adjusted her bright red faux leather jacket and checked her bells for any flaws. It had been a good three centuries since she took part in a bell choir, she hoped she hadn't gotten rusty.
“You ready, Diz?” Nick called over. “And thanks for helping us set this up, by the way.”
Discord sat behind a drum kit, consisting of normal drums, a gong, things that clearly didn't belong on a drum kit, and more, holding a chicken drumstick in each hand. His face was painted half white, half black, and he had a rainbow clown wig on in addition to Groucho Marx glasses. He huffed in annoyance. “Do I look ready to you? My green room wasn't painted blue as per our contract, and my banana flavored galoshes are still in the shop! Of course I'm ready!”
Nick smiled, grabbing the microphone and switching everything on. Blueblood should be having lunch right about now…
And he was, entertaining a very annoyed set of foals from the local schools. He had gotten roped into giving them a tour of the castle and explaining history, but he had just been going on and on about how great he was. All the foals were bored to tears. “Can't something interesting happen?” One asked another. “He hasn't shut up for two hours.”
Blueblood, meanwhile, continued his impromptu filibuster. “...and with my recent workings leading the charity ball to lower taxes for the one percent, I can personally say that I have truly surpassed-”
HELLO, CANTERLOT! ARE YOU READY TO ROCK?!
“What is that infernal racket?!”
ONE, TWO, ONE TWO THREE FOUR!
DECK THE HALLS WITH BOUGHS OF HOLLY-
Later on, many foals throughout Canterlot would remember the ensuing concert as ‘the bestest, most awesome royal concert ever’. Celestia, Luna, Discord, and Nick all agreed that it was a great way to connect with the youth of Canterlot, and get back at Blueblood. Prince Blueblood wanted to get revenge, but much to his fury he couldn't raise a metaphorical finger against an event organized by the princesses, especially not since Twilight had arranged all the permits and proper documentation.
Afterwards, they invited all the foals to Nick's Christmas party, where he regaled them with tales of various Christmas stories...