The very first game I DM'd was a 3rd edition (not 3.5) Oriental Adventures campaign. Me and my friends were a bunch of weeaboos, see. I was the only one who'd ever played D&D before, but it was a few years previously and for 2e to boot. But I put together a d20 Club for my school.

The setting was not!Rokugan; I added some additional major clans and lore (Dolphin and Wolf; the Wolves were exiled for having once tried to overthrow the Emperor). Also in addition to nezumi and humans, I allowed hengeyokai, korobokuru, spirit folk, and custom-made kitsune and soratami races. Most of the OA class options (barbarian, fighter, monk, ranger, rogue, samurai, shugenja, sohei, sorcerer, wu jen) were allowed as well, just not shaman.

I told my players that if they wanted to play samurai or shugenja or otherwise be a member of a Great Clan, they had to be Phoenix. Two of my players did (a shugenja and a samurai). I had them roll a d20; the one who got higher, the shugenja, I pointed to and said "congratulations! You're getting married." The overall plot of the campaign was the PCs escorting the shugenja PC across not!Rokugan to Scorpion lands so that he could be married off to seal an alliance between the Phoenix and the Scorpion, ordered by the Emperor, while meanwhile various factions tried to impede them to stop the marriage from happening. The background plot was basically the runup to the Meiji Restoration: the Emperor was trying to flex her power and become more than just a ceremonial figurehead. It ended up fracturing not!Rokugan, with the Crane, Mantis, and Lion (staunch traditionalism ran up against loyalty to the Emperor) clans uniting and beginning a civil war.

The war wasn't resolved by campaign's end, that wasn't the point; but the players did manage to make it to Scorpion lands and have a big ol' wedding. That was interrupted by a blood sorcerer and a monster attack, but everyone lived.

It was exactly as stupid as it sounded, but we do look back on it fondly.