It's been over ten years since I played Once Upon A Time, but I remember enjoying the game a lot. There is currently a hole in the market for narrative games, as OUAT is only printed once per edition basically and disappears for years at a time, and other games like Aye, Dark Overlord! and Baron Munchausen aren't big enough to be found globally. Then there are games like Story Cubes which isn't really a game but just prompts.
So what I had in mind is something similar to OUAT. But with a twist, I want it competitive and focused. Rather than the cards being events you must mention, they have to be a punchline or ending to the story. The mechanic is constructing circumstances in which playing that card produces a satisfying conclusion.
Everyone has their own ending but they need to play out their cards one after another and steer the story to an ending they need. Basically it's not about telling an enterteining story only, it's about getting to the conclusion by shedding your cards, so if the ending is “And from that day onward, nobody entered the forest again.” you're spending the game to try and introduce a forest, establish a danger, and getting the characters into it, and so on. Using your other cards as stepping stones that let you justify that trajectory. Meanwhile the other players are trying to turn the same story towards their own ending, like “And so the princess married the baker.”
Basically I think I got a very simple game here that I can work on (albeit i need to try OUAT again to see if it's too close to this idea). Perhaps the setting also shouldn't be fantasy and something more original but with a wide appeal.