On a more serious note, an actual osu! storyline would be really cool. I'm not sure if peppy would want to put the effort into making a story mode or what that would even entail, but it'd be a nice thing to have fun with.
Such a thing could include, say, milestones you can get while playing the game that only matter for the story mode. Kind of like achievements, but it wouldn't show up on your profile or anything (but there could be storymode achievements, like XX% completion or Completed <mission name>). There could even be maps commissioned by the staff specifically for story mode, and - if you're really ambitious - it could become a platform for original osu! music as opposed to just licensed stuff. Licensed stuff would work, but original music could be tailored specifically for the story.
It would definitely have to relate to osu! "click the circles" meme, and maybe it could be a way to introduce people to different game modes. Let's say there are four "story arcs"(?), each with a osu character (Peppy, Mocha, etc.) as a playable protagonist. It could either be running through the same story or each character could have their own unique story, which would need a lot more brainstorming and work. Length of stories could vary as well.
Because of the nature of the game - everyone goes on to play other maps and keep farming - I think the best thing for the story would be to leave the ending open ended? Some kind of implication that the protagonist has not stopped her fight against whatever challenges she faced and continues to play beatmaps.
There COULD be pp milestones that trigger interludes or something, but that'd be really discouraging to people who can't make it that far.
