One blackout story that I haven't read about is due to Nitrous Oxide (aka laughing gas, the anesthetic gas you are given at a Dentist's office).
I'm going to spare some incriminating details, but on several occasions over a couple of months I was hosting parties with a tank of pure N02 at the center of it all.
The blackouts were short lived, but numerous and all VERY SCARY. Out of all the stupid shit that I've done, this probably ranks in the top 3. I/We could have died or caused serious brain damage.
The hits consisted of pulling 5-15 seconds worth of Nitrous with the valve wide open, mouth securely wrapped around the nozzle. This was a approx 5 ft tall tank, so standing up to do so was a requisite. A few seconds worth or a few big breaths would induce insta-drunk for a period of maybe 20-30 seconds. A few more, would be insta-HAMMERED with vision non-existant, total body numbness to the point of feeling out-of-body, and hearing an overwhelming "WOM WOM WOM" sound, while music in the background sounded amazing but oddly very "distant" but also very encompassing at the same time -- that said, sound was really the only sensation that would be left somewhat intact, other than vision - but again, was 100% blurred and unable to focus.
Add a few more seconds of breathing 100% Nitrous, and the best word to use to use it "tiimmmmmbeeerrrrr", as in a rigid tree toppling over. Or in this case, stiff-legged fall straight back (unless someone nearby was nice enough to catch you), which in my case led to a hole in the drywall from the back of my skull, which is still there to this day as its always been camouflaged by the wallpaper. Then there is the 30-60-90 seconds of absolutely zero consciousness, face turning blue/purple, and no appreciable respiration. As one returns to consciousness, seizure-like symptoms occur as the body tends to shake and flail about. Over the next 30-60 seconds, you work your way back thru the experiences mentioned above, until you suddenly are 100% sober as Nitrous has an incredibly short half-life (seconds).
Experiencing the last stage mentioned wasn't nearly as scary as watching one of your friends fall over, turn blue, and seizure back to life. One time, a friend literally laid there not breathing for probably close to 2 minutes, and I had my phone in hand preparing to dial 911.
When mixed with Oxygen at around a 50/50 ratio, administered through a mask at 6L/min, Nitrous is a VERY pleasurable experience and worth every penny in tandem with a dental procedure.
Taking pulls off the Nitrous tank w/o stopping to breath in ANY oxygen is the fastest way to blackout via inhalation that I can think of, and due to it's half-life is probably the only reason why any of us didn't die.
There is a good reason why it was used as the ONLY analgesic without any local anesthetic during the early days of pre-modern dentistry. It's very effective.
Otherwise, countless drunken black-out scenarios that always led to me spending the next day puking my brains out. That said, I was never as functional as most of you claimed to have been during it. Enough over the high-school and college years to completely turn me off from anything more than a couple glasses of good red wine or small batch bourbon.
My one and only functional, multi-hour "black-out" experience was my first time rolling on X. Out of the dozen time I've taken it, I believe it may have been the purest MDMA (unless it was cut with something else to have caused this), as I had never again gotten that bad.
I'm happily heterosexual, married even to a hot woman.
Well, on that night, I was taken to an "underground" gay bar, gave and received a back rub from a cross-dresser, randomly squeezed strangers tits, and spent no less than 2 hours in at least two locations being taken advantage of via making out with a gay guy. I came to as we were leaving someone's house at about 4am, and had enough flashbacks the next morning to have a reasonable idea of what took place.
I had to replace my only debit card after that night because I chewed it to pieces from wanting to grind my teeth sooo bad during the trip.
A week later, I saw a friend at a table at a local bar. I approached him, and saw a guy that looked vaguely, distantly familiar. I watched him as he whispered something to the guy next to him, and they then gave each other a high-five. It was the guy who took advantage of me (really weird saying that as a dude), and convinced he was telling the guy about how he made out with me, etc.
Anyhoo. Never told my wife that story. SHe wouldn't take it well (despite it happened before we knew each other).