Hello Dreams! Coming up with events for a slice of life site that people will fully engage with can be tricky. In my staffing experience, events I thought would have drawn interest via gathering characters into an area for a celebration or activity as a means of easy connecting with one another, ended up not gaining enough intrigue to be what I felt was truly successful. From my experiences over the years, I've found what peeks greatest interest from members seem to be events involving some form of catastrophe or something including the idea of romance.

For further explanation-- Catastrophes, as in natural disasters of sorts. Maybe there's a power outage, a snow storm, thunder storm, tornado, flood, etc. for characters to endure with others. Anything that's chaotic and exciting, but doesn't have a long-term effect you're uncomfortable with regarding your site's plot. With romance, perhaps there's a blind date event, a formal pageant, or some form of season-themed dance. A type of environment where there's a range of shy-blundering, flirting, or "shipping" possibilities. A contest could be incorporated into this type of event, too, though not necessarily needing to be directly themed around the same romantic nature. Every community is a little different than the other, thus setting up a poll or discussion to get a feel of what themes or contests they'd prefer may also be of an advantage. 

In all, though, my advice is something that's somehow thrilling whether it be in a "fluff" or "danger" mindsent and gives members a reason to feel amped. If you're hoping to use these types of events to lead up to a greater plot surrounding your site, you can find ways to incorporate such themes or clues through these passages. Hope this helps!

Kida's given good advice, but I'll just add a couple of things:

-Catastrophes don't necessarily have to be natural disasters! Think of things like a bank robbery or a murder mystery (even one of those 'dinner party' types with actors), and those can give people plenty to play around with. They will probably require more legwork from the staff, but I think playing those kinds of NPCs can be fun too!

-For a slice-of-life site, more lowkey things like balls and festivals, as you said, can work well, but you can expand beyond those too. What about hosting some sort of event at a resort? A carnival or circus coming to town? A scavenger hunt at an amusement park? The opening of an ice-skating rink for winter? Halloween costume party or haunted house? Cruises? Those are other settings that people tend to get excited by, so don't be afraid to just capitalize on the ""aesthetic"" aspect of those things and then letting people free to do their own stuff.

-Prompts and randomized pairings. I know these can be unpopular, but listen—you can do great things with prompts! The trick is to not write a generic prompt that doesn't give people any reason to talk or continue interacting. I had a pretty good reception when prompting things like "person is given a love letter not meant for them," or "person is let into the wrong hotel room," etc. The trick with prompts (and open threads in general imo) is not being afraid to make them weird or outlandish in such a way that people likely will have reason to continue interacting beyond two or three posts.

-Contests/competitions can work too, whether IC or OOC. I've seen sites that divided people up into teams and did a posting challenge to see which team posts more. I've seen advertising or graphics challenges. People can be rewarded by lowering post requirements for their next character, by giving a free pass for the next Activity Check, with pixels, etc. It just depends on what works for your site. IC competitions can be a fun way to build rivalries and to give characters an activity to do—on my own site we're going to try to run a race through a corn maze in the spirit of Halloween.

@kida and worldiezilla, thank you so much for all your experience, opinions, and helpful advice!

I've never thought to do a catastrophe or a prompt to get people involved. I've been wanting to do a scavenger hunt for a while now, but wasn't sure how, exactly. I was also considering doing a love prompt for Valentine's Day. The ice-skating and carnival is a good idea, and may actually use the former in some sort of Christmas-themed event.

And, I'll definitely keep some of these challenges and competitions in-mind, though!

I appreciate your well-thought out replies and your willingness to help. God knows I need it, lol

I'm still open to any other suggestions, advice, or critique, though. The broader I expand my horizons, the better.