So this is kind of already a thing, more or less, with things like full moons, holiday events, and weddings. But I think it'd be fun to have more roleplay events. Things that encourage people to act in-character rather than just chatting normally.
Things like...
-More advancement with the Walpurgis Knights, they're currently one of the most exciting things on the server roleplay-wise (even if Bjor himself is against them lol). I know they're managed by Narcissa so I'm not sure how much control the staff actually has over them, but scheduling public speeches and increased levels of propaganda would be interesting.
-Once Quidditch is back, official Quidditch after-parties might be fun, instead of everyone getting wasted in their commonrooms.
-School assemblies, where every so often the school will meet in the Great Hall and discuss matters of importance. Current events, class changes, etc. It could deliver updates in a roleplay friendly way, such as announcing the release of a new spell by saying "The jinx (name) has been increasing in popularity on school grounds, keep in mind that jinxing other students is forbidden." It wouldn't operate as a replacement for announcements, more a way to encourage people to read them and get the full story.
-Allow players to subscribe to The Daily Prophet via owl. I'm not sure how this would function, but maybe you can pay a one time (or monthly) subscription fee and then start receiving copies. Like the school assemblies, they'd list roleplay related events. It could hint at new released features (for example, an article on increased werewolf sightings). I'd be willing to write Daily Prophet articles sometimes, if volunteers are needed for that.
-I know jobs are being planned around people who are graduated, but it could be interesting to have student internships for jobs. They'd be payed maybe, 15% what a graduate would get payed for that job. Let's say someone interns for the Ministry, with the housing department. They wont have control over anything, but they'll be able to write reports and help keep track of things.
-Guided Hogsmeade trips for students under 3rd year. You disable the year restriction for however long the field trip lasts, then anyone lingering gets booted out once it's over. I know it's canon that third years get weekend trips, but they can go whenever so going on a guided weekend trip might not be as fun.
Anyways, here's all my ideas. I'm sure some of them are already planned but the general idea is just more roleplay events, not any of these specifically.