I found a server that runs Minecraft events and they are almost always themed around Origins. They do apps for new events and they also have a modded zombie event in the works that is taking a while.
Most events split players into 2 or 4 teams and each team gets a specific origin. The host says it is over a week but from past events it usually ends up being about 4 days.
The next event is free for all and you get to pick your own origin. They also warn that the rules are more lenient than a lot of event servers so people should read the rules first.
Origins Event Server With 100 Players
GG.MINEWIND.NET New Server IPValentines Build Battle Event
This is a Minecraft server running a Valentines themed Build Battle event. The whole point is to hop on and make cool builds around the Valentines vibe and try to impress everyone.
From what I can tell it is focused on creative style building and short events instead of super long grindy gameplay. It feels like the kind of place where you just join in build something fun and hang out with other players for the event.
They are on version 1.21.8 so you will need that to join. If you like building around themes and trying to win little build battles this server looks pretty fun.GG.MINEWIND.NET New Server IP