What system do you use?
"Everyday Magical Girls," or whatever we end up calling this game, is intended to be played in Tri-Stat dX rules. They're freely available on the internet, as is a character creator to crunch the numbers for you.
The character creation rules might be a bit involved, but they allow enough flexibility to make just about any sort of weird character one could want. Which makes them ideal for a game like this. The other mechanics are simple, and can be summed up as "roll 2dX. If the result is equal to or below your stat+relevant skill, you succeed." For this game, we use d10s.
Characters are built with 150 character points and 40 skill points. They don't need to be magical girls. They could be more like Kamen Rider or other tokusatsu heroes, or whatever other concept fits into the general setting well enough. The Masked Rider idea is mostly for those who wish to play a male character but don't want to wear a tuxedo and throw roses.
The Setting
The game takes place in Tokyo, Japan, during the modern era. Magic is real, but it's a closely guarded secret. The same can be said for scifi-level technology. In either case, they're more common among aliens, people from other dimensions, time-travelers, ancient cults and conspiracies and other such secret organizations. Generally, when mundane people encounter magic and other fantastic events, they're covered up by one group or another. Or misinterpreted as something ordinary. Or no one talks about them becuase they doubt anyone else would believe them. Still ,there might be some "magical girls spotting" communities on the internet…
