I once hiked from the Sea of Galilee to the Mediterranean in three days, and on the way lost two pints of blood.
-I stayed up past 11PM one time.
-Got married.
[sup]Damn, I got nothin’ but some of you have some pretty impressive accomplishments![/sup]
Skydiving (once), caving (once), ROTC basic training (Air Force, but I did get to eat rattlesnake and C-rations and fly in a T-38 trainer), and feeding cages full of mosquitoes blood meals with my forearms (once).
Extreme reading is more my thing. I’ve done extreme length (the entire Decline and Fall of the Roman Empire), extreme yuck (forensic pathology texts), extreme politics (The Protocols of The Elders of Zion), and extreme crap (too many to list, but we can start with The Da Vinci Code and two, that’s two, Bulwer-Lytton novels).
It’s not nearly on the same level as skydiving or bungee jumping, but I went zip lining through the rain forest in Costa Rica last year. It was pretty scary not only because it was so high up, but also because you think for sure that you’re going to smash into the tree at the end of each line.
I’d rather not say as numerous laws were broken across multiple states.
The most extreme unintended thing I’ve ever done involved bunny hopping a mountain bike.
Onto the hood of a corvette that was coming towards me down a one-lane bike path.
Wheels got trashed, and the Vette’s hood and windshield got smashed, I’m pretty to entirely sure. As did the roof, I think. But I survived it.
Most extreme intentional thing I’ve ever done that I can talk about without being arrested. Jumping out of planes? Everyone does that. Going up in a homebuilt experimental parawing parachute plane made out of a wheelchair and some other stuff? It’s a good start of an answer.
Proto-bungee jumped off a bridge on the Thames. The cord was attached to the successor’s successor of the bike I folded on the Vette.
Bicycled a double century. (200 miles) Every. Single. Joint was chafed and bleeding at the end. Seriously. I was just oozing blood standing there.
Oh, stayed up for five and a half days once, the first three involving heavy physical exertion, and then I just decided to ride the wave.
Note: proto involves the fact that there was a bungee cord… but, uhm, well, it wasn’t exactly a professional installation.
I stayed up for 72 hours straight studying for finals my senior year of college. I got ‘A’'s on all of them including the highest score every recorded on a famously difficult test. I decided to celebrate by going out drinking at the end of it and got piss drunk and decided to go to bed because I was getting exhausted and hallucinating.
The next thing I knew, the Vietnam War was happening all around me and I had to take cover. I fled out of my apartment, dug a trench with my bare hands in the damp and dank earth, covered myself in mud for camouflage, and started marching again to find my unit when it looked liked things were all clear. I made it about 5 miles before I had to sleep again so I found a place to stay. It was a graceful porch swing attached to a stately house and I was thankful for what I had for refuge. I woke up when the sun rose with the birds chirping thankful that the enemy troops were nowhere to be found but I had no idea where I was or how I got there. It took me a few hours to find my way back home because no one would talk to me because I looked like a lawn jockey pulled from a toxic waste dump.
I didn’t get any medals or ribbons for my Vietnam War Service in New Orleans in 1995 but I think I should have. I was willing to do anything to protect my country.
Wow. Let me say that again, Wow!
I never even considered staying up for so many hours in a row! I can’t imagine.
I am truly impressed by both of you! It’s madness, but it’s impressive.
I survived the “ultimate scunge” on my first caving trip (less than a foot floor to ceiling, mostly filled with scummy water - on your back with just your nostrils sticking out), made it through the “organ grinder” on another, and hugged the least likable guy on a caving trip for an hour to keep him warm after he dropped our safety rope down a hole on a third trip.
I did a bungy rocket once and the Big Drop on the Tower of Terror at Dreamworld.
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Went backpacking/trekking solo a couple of times in Tibet in the 1980’s for about a month each time.
Hit the button on a nitrous injected Buell motorcycle in first gear ( despite bold warning in the installation manual not to do that ). Set my own broken leg after a bike crash. Seperate occurances, btw.
I once sat on an airfield while a Marine platoon did an airdrop around me. At night. Twice. My Dad was the Jumpmaster. I think I was…11ish.
A big deal for me, anyway. 
Eh, a few years ago I got mad at my stepmother, quit my job, bought out a company and went into direct competition with my parents.
I don’t know if that’s extreme, but it’s what I got.
Stood on a corpse.
Barefoot.
I once got lost in the Alberta Badlands and found my way out, only making myself about 30 minutes late in the process. But seriously, try not to get lost in the Badlands.
If I told you, I’d have to… aw you know.
When I was young and taking a Semester in England, some friends and I called up Windsor Castle to find out visiting times. We were told visitor hours extended to 5:30PM. When we arrived at 4:00PM, the site was closed. (Something about the Queen being in residence.)
We decided this was grossly unfair and decided to try around back. After walking a few miles and climbing some fences, we ended up getting chased all over by angry British soldiers with loaded machine guns including a jeep-mounted 50-caliber. When they finally cought up to us, we had to listen to them repeat over and over and over, “You know, if this was the White House, Reagan would have had you shot already!”
A few years later, when I lived in Washington DC, I was really drunk and tired after a party in Georgetown. While walking home I decided that climbing over a 12 foot tall wrought iron security fence was a good idea for a shortcut. In my drunken mind the place was owned by some rich Japanese guy. Imagine my surprise when machine-gun armed soldiers chased me back over the fence yelling what I later found out was: “Stop or we’ll shoot!”
I had climbed over the fence and walked/stumbled 35 yards into the new Soviet Embassy compound! My glasses flew off as I rescaled the fence and ran back into Georgetown. This was useful in proving to a softball teammate who was a Sovietologist that I had actually been there.
I was one of those walkers 
Of course, my hiking companions weren’t as brave, so I spent a long time waiting for them at that part.
We hiked Longs Peak after leaving from home at midnight after not sleeping and having worked that day. Made the drive, did the round-trip hike, drove back home (about three hours), where I had just enough time to grab a quick shower and go do two hours of hockey practice that night (and half the team didn’t show up so there was plenty of ice time)
On the topic of 14,000 foot tall mountains - I’ve hiked a little over half of them in Colorado (30 summits so far), sometimes as many as five summits in one day. I’ve done the half marathon up Pikes Peak for the past 5 years (7,815’ of elevation gain over the course).
Skydiving, check. Ziplining, check. Rafting class 5 rapids, check.
I ran a 50 mile trail race, all above 10,000 feet of elevation, and with more than 9000 feet of gain over the course.
Not sure what to do next 
Y’all are a more adventurous bunch than I am!
The best I’ve got is wondering around the Paris metro at 2:30 in the morning with a couple of other drunken 17 year olds.