NOTE: Don't take this seriously because this is just an idea.
Anyway, I was thinking of a world championship where the Monaco Grand Prix, Indy 500, and the 24 Hours at Le Mans are brought together.
The world championship is 12 rounds, including the mentioned three races, and instead of bringing an F1 car, an IndyCar, or a Le Mans Prototype separately, you can create a car that can race in any discipline.
There's no need for restrictions on whether you can race it in either open-wheel or closed-wheel, open or closed cockpit. I can call this series a free-for-all race, inspired by mixed martial arts.
So anyway, what do you think?