One idea could be to explore what happens when a new and very strange artifact is added to the museum. Maybe it has some sort of magical power that affects all the exhibits in unexpected ways. For example, it could make the dinosaurs start speaking in modern languages or the statues come to life with different personalities than before.
You could also create a fanfic where the exhibits decide to put on a big show for the outside world one night. They plan and rehearse in secret, and then when the night comes, they manage to bring the entire city to the museum for an unforgettable event. This would involve all the different characters from different eras and cultures working together in harmony.
One idea could be an OC who is a time - traveling historian. They get stuck in the museum at night and use their knowledge to communicate with the exhibits in unique ways, like deciphering ancient languages on the tablets. Another plot could involve an OC with the power to bring the museum exhibits to life outside of the museum, leading to chaotic but fun adventures in the city.
Well, perhaps the OC is a time - traveling artist. When they end up at the museum at night, they start to paint the exhibits as they come to life. But their paintings start to have strange effects on the museum world. For example, if they paint a dinosaur with wings, it actually grows wings. And the OC has to find a way to reverse these changes before the museum is completely transformed into a chaotic and unrecognizable place.
One idea could be that the characters from 'Night at the Museum' accidentally end up in the setting of 'Tower Heist'. The museum exhibits come to life in the high - rise building where the heist is taking place. Maybe the night guards from the museum team up with the 'Tower Heist' crew to stop an even bigger threat that is targeting both the museum artifacts and the money in the tower.
Another idea is to create a story where the rules of the Grail War are changed. For instance, instead of seven Servants, there are only three, and they have to complete different tasks to win. This would completely change the dynamics of the story and lead to new and exciting interactions between the characters.
One idea could be that the night guard has a special connection with one of the ponies. Maybe they share a common interest in magic, and the pony helps the night guard understand the magical elements in Equestria better.
Perhaps there was a night when a new night watcher was on duty. He was really into ancient history and while walking around the mummy exhibits, he felt like the mummies were telling him their stories through the ages. He started writing down his thoughts and later found that some of his ideas were actually similar to the known historical facts about those mummies.
One idea could be that Naruto discovers he has a special power that only activates at night. For example, he might be able to communicate with nocturnal animals and they help him in his ninja missions. Another could be that at night, Naruto's appearance changes in a way that gives him an edge in stealth, like his hair turns black to blend in with the darkness better.
Perhaps a fanfic where a night blooming cereus is the centerpiece of a love story. A young couple meets near the cereus every night it blooms. They share their dreams and fears under the moonlight while the beautiful flower is in full bloom. But then, one of them has to move away, and they struggle to keep their relationship alive, with the cereus serving as a symbol of their love.
One idea could be to have Naruto characters participate in the Holy Grail War. For example, Naruto himself could be a Servant, perhaps with his chakra being a unique form of mana. His skills like the Rasengan could be reimagined as powerful Noble Phantasms. Another idea is to put the Fate Stay Night characters in the Naruto world. They might have to deal with things like ninja clans and the politics of the hidden villages while also trying to find a way back to their own world.
One idea could be to explore what happens after the events of the play. For example, how the relationships between the characters develop further. Maybe Hermia and Lysander have some small arguments as they start their new life together, and they have to learn to overcome them, just like any real couple would.