I've touched on it briefly here but I used to LARP in my college days. Mostly White Wolf stuff though my friends also formed their own variant - Echoes of Empires, which, even if you do larp, you probably haven't heard of. Mostly Vampire: The Masquerade, but also Werewolf and Changeling. OWBN at times. Tabletop was of course a thing that happened as well. I have some dear friends who are still way into it, but for the most part the group as a whole was poisonous, manipulative, incestuous, gossipy, society misfits who were content on getting by by doing as little as possible and sponging off of whatever system they could. One of the "ringleaders" of the group, hell, he's in his thirties and still lives off an allowance from his rich dad or something. Has never had a job. The allowance isn't enough but he can full time LARP and that's all that matters right! Right! I was cool, yo. Said with all the dripping sarcasm you can imagine.
Zomg. I retired undefeated from Car Wars and Battletech at the ripe old age of 13. Curious to find my "peeps" in college, I attended one meeting of the "RPG club" where I found 8 dudes and a chick who were big into Vampire:Masquerade. Which was a game that got you beat up by D&D nerds. In 1992. I'm a pretty big nerd. I can walk the walk, talk the talk. I'm a member of LASFS, a group of gentle nerds that makes me feel like The Fonz I'm so cool compared to them. I think they'd kick the shit out of anyone LARPing V:M. It amazes me that game still exists. 
All over the place. That gender ratio sounds about spot-on too, bonus if the female was on the land-whale side. One of my besties really, really, really fucking enjoys LARPing. I don't really get it, at this point, at all. It seems like far too much work on her end to be any fun, and moreover, I have a lot of difficulty understanding the appeal of what is, essentially, total escapism. She even does a LARP where none of them have any super-powers, I guess it's like an SCA variant. At minimum, if I am going to pretend I'm a different person for several hours, I want some cool powers to throw around. I don't want to be gathering herbs in a garden for some other person's feast. I also wonder how one must feel about their life in general if one's favorite form of entertainment is, essentially, pretending that that life is not real by engaging in role-play in fantasy, alternate realities. However, love the gal, and she's pretty down to earth otherwise, and LARPing isn't hurting her, so who am I to pick on her recreational activities? They were certainly the outcasts of the outcasts and in general I wish them what is coming to them, including what is sure to be a lot of tooth and mouth pain. Hygiene was none of their strengths. I'm well rid of them.