My megaproject ideas are mostly pretty standard. I'd build a high speed rail network across North America, and build and expand metro and regional rail systems in and around every city. I'd turn all cities and suburbs into fifteen-minute cities. I'd decommodify housing, and build ten million units of public/social/non-market housing, mostly three bedroom units. I'd link those last three policies together by building TODs around the new Metro and rail stops. And I'd build bicycle networks in every town and city and connect them to the TODs. I'd build bridges and walkways across skyscrapers. I'd put a bidet in every American toilet (uses less water than toilet paper apart from being more comfortable). Fiber internet in every home. A heat pump in every home. An induction stove in every kitchen. Phase out fossil fuels and power everything with Pumped Storage Hydropower and Geothermal. I'd make the US go Metric.
But my truly crazy, obsessive idea would be to bring back the French Revolutionary calendar. Or I'd purge all French influences from English.
Write into law that there is only one type of Christianity allowed. Every five years the knights of columbus and the freemasons select their top guys for a gladiator fight. If the Knights win then catholicism is the official religion for 5 years, if the masons win it's protestantism.
The Russian Orthodox Church would just start a religious order staffed by Russian MMA fighters and it would win every year
If it's Catholicism, do the pope and Orthadox Pope duel?
If it's protestantism, just IRL fortnite between all like 20,000 protestantism sects