I've also found similar things in the "Burner" community (ie: people who participate in Burning Man and the many regional events).
I don't mean to suggest that everyone would have the same interests or that there aren't also a lot of people who just go to the festivals because they're fun festivals. Still, it has ticked a lot of the same "boxes" for me.
Ideally, it's a community that's based on participation. When you go to a burn, the idea is to bring something to contribute, whether it's interactive art to play with, food to share, a bar with great cocktails, or a comfortable place where people can hang out and relax in the shade.
I enjoy it because it provides both an outlet for my creative/artsy interests as well as my enjoyment of building things and working on interesting projects with other people.
When I go to one of the burn events, there are more people interested in talking to me and working with me on stuff than just about anywhere I've been and I'd imagine this is a lot like the hacker space scene. It's been a fun way to meet people with similar (or different) interests whereas at work I only interact with one or two people who I might do those sorts of things outside of the office.
If I go to another region or town, I can be reasonably assured that if there is a burner community, I'd have a place to socialize and meet people to work on projects with. The concept has spread worldwide so burners or people with similar interests are easier to find than I would've imagined.
As far as initiations and rituals, there are some good examples. The "burn night" is like a huge communal party and walking around I get wished a "happy Burnday". When you arrive (especially as a "virgin" at your first event) you can get a playful spank with a paddle or (if you don't want such a thing) maybe a hug or at least some smiles. People often give nicknames known as "burn names" or "playa names" that are probably closest to the nicknames people get in the military (sometimes jokingly deprecating, sometimes honorific, etc).
Instead of strict commandments or laws, there are principles. Principles allow for interpretation and discussion but still provide a framework and a unifying set of things most participants value to at least some level. Examples are participation, civic responsibility, communal effort, gifting, de-commodification, self-expression, and leaving no trace (since the events typically take place in a camping setting).
I know that Burning Man and the associated regional scenes have a reputation as being just big parties all about debauchery and crazy outfits (or none at all). While there is certainly an element of hedonism should you desire it, the communal effort and focus on working together and being yourself while not hurting anyone else or the community have really impressed me.
I've been going to some regional events for several years now and while I don't live the stereotypical "burner" lifestyle every day, I love having a community in most places I go and a group of people I can meet up with and find those with common interests who want to work on projects together.
And the best part is you get to share all of those projects and brainstorms with loads of other people when you attend one of the events. It's like a huge artsy, techie pot-luck where everyone brings something to share and gets to go try all the things the other people brought along. I'm always astounded by the amount of creativity, talent, and work on display when you get several people (or several thousand) all trying to bring their "A-game" to share with everyone else.