In the late 90s I helped a buddy of mine move from N. Virginia to Denver for law school in mid-September. We both raced mountain bikes in local circuits around D.C., so the first thing we did when we got to Denver was look for some trails to go riding before I had to go back. We found a trail on some 1998-era website that showed a 15-ish mile loop in Pikes Peak National Forest and went for it. The trail map that we printed from the website showed a simple loop, so we set off for the mountain in t-shirts and shorts, one water bottle each, and didn't tell a soul what we were doing.
Fast forward several hours, the sun was beginning to set and we found ourselves not on a simple loop but on a network of criss-crossing trails that took us on all sides of the mountain. Once dusk hit and the cold settled in we started to get worried. We tried back tracking but there were just too many intersecting trails to get a solid fix on where we were. Eventually the sun set entirely and it got too dark to ride; we couldn't even see the trail and were constantly riding off into the woods. We had a conversation about how we were going to manage the night with no food, no more water, and no warm clothing. It wasn't pleasant.
We decided to trudge on, at this point it was so dark that we could barely see what was in front of us. At one point I picked up bike tracks in the snow, barely illuminated by the sliver of moon, that looked familiar. We followed them for a few miles until we found the same area with a large rock that one of us had eaten shit and wrecked into shortly after having started off. An hour or so later of carefully walking and following the tracks we came up on by buddy's Explorer in the parking area. I still remember the thermometer reading on the dash showing 34 degrees. To this day I know that it was 100% luck that we managed to get back there.
We went back to his place, cleaned up, found a bar and proceeded to get really fucked up.