Knot Tying. Sure, there's an International Guild of Knot Tyers, but it's a rather small group.

Be vewwy vewwy quiet. We're hunting cell towers.

"You know Pokémon Go? It's like that."

I have quite a few obscure hobbies due to ADHD...

I'm super into collecting vintage analog music equipment. Old analog synthesizers and reel-to-reel tape machines to be exact. I also make music on them, but to be honest that's kind of a secondary thing haha.

I play a little bit of everything. Drums, guitar, keyboard, bass, etc. I'm probably best at drums though and have been playing for the better part of 25 years. Currently in a punk band and a desert rock band.

I'm into programming (web dev is my career) and embedded systems. I make a ton of various things with arduinos/raspberry pis. Often I'll try to combine the two and make midi/cv controllers for my synths.

I got into 3d printing a couple years back and have since been going down the rabbit hole of CAD with fusion 360/blender/etc.

I also got really into making video games for a bit in Unity. Started work on a VR game and have been meaning to get back to it.

Speaking of VR, I'm not a huge gamer but definitely love playing Beat Saber and Pistol Whip (both VR). I'm in the top 1000 or so in beat saber, but I was #1 globally in pistol whip for quite a while. I imagine I'm probably still top 10 at least.

And probably my most obscure hobby: Poi

Most people have no idea what it even is, and once they find out, just assume I'm a rave kiddie. I mean, I kind of am, but I legit love the art of poi.

I collect wrist watches and intend on learning watch repair soon ish

Marxism

Fixing small things. My friends or family need something fixed that doesn't require a professional. I like figuring out how to fix things or at least providing a temporary solution. I do it because I'm helping someone, also I'm building my skill set. A basic search of answers and videos teaching me how to do it properly most times is easy to find. If not I find a way to create a safe temporary solution until they can have one come in. Very fulfilling, especially if you like a challenge.

Sim racing isn't necessarily too quirky or obscure but I do it to maintain some sort of maybe possibly ADHD. Doing laps around a track really helps with getting myself used to focusing.

It's especially helpful because each lap around a race track tends to be only 1 - 2 minutes, which is a relatively easy amount of time to keep focus at any one point in time, but keeping it up for consecutive laps and remaining consistent as time builds up in small increments is a different kind of joy to me.

I am something of a skills collector: Bicycles (roadie/former amateur racer), cars (mods/engines/paint), composite prototyping, metal machining, home foundry metal casting, embedded programming, analog and digital electronics design, reverse engineering, KiCAD, PCB etching, motor controls, python, CPP, Forth, woodworking, Linux desktop, Linux kernel deep dives, computing hardware, open source software, Dune, Asimov, SciFi, astronomy, telescopes, designing and building optics, 3D printing, CAD design, FreeCAD, Blender, cooking better than the best restaurant foods, Asian cuisine, psychology

I am a generalist, but a swiss army knife, I know about and do a lot, but I am like the worst scissors you've ever attempted to carry and use. I can get the job done, but am well aware I am not a master of any of these.

In addition to general learning which might be my favourite, I have multiple.

Maybe the most niche is a historical reenactment and historical costuming. Latter usually based on extant garments or garment finds. I try to get as close to the original in techniques, tools and materials using the best evidence I can find.

I also plan things that will never happen. I decorate houses and apartments on paper. I make extensive plans for travel that I can never afford unless I win in Lottory. Which I even never play.

I spend absolutely too much time playing with spreadsheets.

Sim racing.

It’s difficult to talk about it without people dismissing it as just a video game with a steering wheel.

I build and optimize molecules using computational chemistry software for fun.

Hah, I like your hobby actually.

I've actually managed to upgrade Cistercian Numerals from decimal to hexadecimal, while still being backwards compatible.

https://youtu.be/9p55Qgt7Ciw

Handspinning. I do a lot of fiber crafts.

I'll say me writting my homebrew DnD world. It goes in pair with me using ObsidianMD, I love the tool i'm using and i'm having fun specifically in the making of polical cities more than in the making of combat senarios. My mom knows about it and sometimes asks, Dad finds it stupid, and I don't talk about it with anyone I used to atlk about what I write to two friends, but they are coming to my session in september so now I have no one esle to bring it up

Lockpicking tends to be my most misunderstood hobby/interest.

Writing fanfiction

Similar to another reply about shorthand, I practice with my own steno-typing keyboard I 3D printed as a hobby. I'm steno-typing this very message! (Very slowly)

Running. Ok, I know it's not obscure, however, if you say you're a runner, or that it's a hobby, you're frequently met with hostility, or people trying to talk you out of it. The amount of times people have said "running is bad for you, you need to stop" is insane.

listening to number stations

I love plushies. I have an ever growing collection and love just browsing plushies of all sorts when I'm online. I just really like cute things. But as a 28 year old man with a beard, it's safe to say I'm not exactly the spiting image of a plushie collector, and most people are definitely not interested in talking at length about it with me.

I like to play with dos. Every once in a while I start looking for games and programs trying to recreate the computer my parents used to have. I've also gotten into randomizers recently. Currently in the middle of a 3-person multiworld playthrough of Stardew Valley.