To celebrate Fate/Extella being released on the switch, rate-up Gacha and possible event in July.

Depending on level of preparedness/investment/laziness, different things could occur.

Ultimate laziness: Rate up Nero, Tamamo-no-Mae, Altera, (maybe Archer). Second chance at Extella CEs

Less laziness: THREE Gachas, one for each faction with new Extella themed CEs. Each faction gacha has a rate up for their leaders and lieutenants.

Problem with this is that the factions are hilariously unbalanced in terms of rarity in F/GO so you can't just push it out into a gacha as is or can you

Red Faction: Nero, Garcher, Cu lancer, Li Shuwen, Gawain (one story lock 5☆, one 4☆, two story lock 4☆, one 3☆)
Blue Faction: Tamamo, Karna, Lu Bu, Elizabeth, Medusa (two 5☆, one 4☆, two 3☆)
Green Faction: Altera, Jeanne, Iskander, Gilgamesh (two 5☆, two limited 5☆)

There's two solutions. Solution A: each faction gacha only has a leader rate up. Solution B: We pump up the lack luster gacha, tone down the ridiculous gacha, and introduce new servant 4☆ Caster Archimedes. Solution C: Make 5☆ Nero

Red Gacha: Nero, Gawain, Archimedes, event CE
Blue Gacha: Tamamo, Elizabeth, Archimedes, event CE
Green Gacha: Altera, Caster Gilgamesh I don't like this solution, but I can't think of an alternative, Archimedes, event CE

Secret three hour long gacha each day featuring Artoria rate up.

Actually doing work: Mushroom Kingdom Tour event.

Easy, laid back event. Only requirement is clearing Fuyuki.

Story: You find a strange singularity that takes you into a world full of yellow and green mushrooms. The three princesses of this kingdom (Nero, Tamamo, Altera) invite you to have cake with them when you are all attacked by a mysterious antagonist. They entrust you with the Regalia, which helps them maintain this world, before they are taken away by a giant mushroom [Nasu]. You end up dropping the Regalia and shattering it into multiple pieces which then fly off. There is one Regalia piece for every chapter. Because the Regalia is shattered, the world becomes dangerous and fragmented. Monsters appear and you have to use Warp platforms in order to move from one World to the next. Vizier Archimedes accompanies you on your journey, giving commentary and is available as a Story Support Servant. Each time you finish a world, you look for the princesses and are given a "Your princess is in another castle." [After completing the final world,](s/ "Archimedes turns around and betrays you and is the real final boss.")

Completing the story rewards the player with a commemorative CE featuring Tamamo, Nero and Altera with the cake.

Event CEs would have various servants in Nintendo-themed costumes.

There would also be an event Mystic Code of the Extella master outfit.

This would actually be hard to do right: Mushroom Kingdom Tour+

Same as before, but each chapter is a Mario styled World with a nasu-verse property theme, going back chronologically. So for example, there would be a Witch on the Holy Night world, a Melty Blood world, and yes the final world would be Tsukihime with an Arcueid cameo. After the Tsukihime world completion, you're taken to the final boss area, which has a demon pillar sized Nasu mushroom.

Event currencies would include Gold Coins, Hanafuda cards, Ema boards.