All the Chaos Computer Events are like a different dimension. You can leave your laptop somewhere unattended and the worst thing that may happen to it, is that someone plugs it in to charge.

GeoCaching for offline (semi-online). When I learnt about it, it blew my mind. There's literally trillions of hidden 'stashes' all around the world that people have hidden. In bushes, up poles, behind signs, etc. Every city. Fields, forests, everywhere!

In the stashes you'd find anything from a piece of paper to mini figures or a bullet! You write your name on the paper and date it. Then you hide it and go hunting for more using the Geocaching app.

Makerspaces/hackerspaces

Basically a bunch of fellow geeks nerds and makers. A few joking comments can spiral into awesome discussions or insane projects.

The biggest bit is just having somewhere you can geek out and have people's eyes light up, rather than glaze over.

On top of this, you gain access to a bunch of awesome tools, as well as people who know how to use them, and often want to teach and share. It varies a lot from space to space, but most have a laser cutter and 3D printers at least.

Shout-out to r/TESLore. I remember the exact moment I was hooked: Someone started her comment with the phrase: "We all know what the enatiomorph is, where it comes from, and how it's formed, but..." and I've gleefully been indulging with those other weirdos ever since.

I'll put my vote to Deep Rock Galactic for online. It's a game (that you MUST check out) with one of the most wholesome communities ever. Most people are super nice in the chat and I've made a friend or two (for me that's a lot - I'm extremely picky cause I feel very nice with the amount of friends I have already)

Both of mine are offline and involve something in an everyday space that others wouldn't understand the significance of or possibly notice at all

First, the Hash House Harriers, the self-proclaimed "drinking club with a running problem". It's fun seeing chalk marks on pavement and knowing that a hash had recently passed by, even if it's been some time since I've been.

Second, geocaching. Tons and tons of containers hidden around you that you might never see if not actively looking for it. It's always a blast running into another person suspiciously looking about under a bench or whatever.

Offline: a martial arts dojo. A bunch of goofballs wearing Japanese undies play fighting and smiling.

Offline: kink spaces. A bunch of goofballs in fancy undies play torturing and smiling.

NeoCities always feels like a portal to an older internet

When someone I know who I went to different schools together with invites me to their school (as someone who never liked my own).

Offline, go to any jam band concert like dead & co, dopapod, the werks, or dark star orchestra or glitchy bass music concert like Mersiv, Tipper, detox unit, or 3AM. even better, go to a small music festival held on private land (no law enforcement)

I saw the barter system in action, folks just giving away Hallucinogens and pretty rocks, lots of sharing and hugs and general positivity. Even saw one of the homies having an impromptu magic the gathering match on a big flat rock next to a river. They both just happened to bring their decks to the festival.

midnight.pub - Chill place for people to write extremely niche and detailed blog posts.

IRC - Lots of technically competent people who are fun to talk to.

rawtext.club - I haven't joined this because I don't think I would really contribute much but it is a good idea.

Or just Gemini/gopher in general are cool places to be.

vogons.org - we're all stuck in the 90's, tinkering with old computers.