Numerous.
Many years ago, I was on a mountain bike ride that was more of a gravel grinder ride (before those bike were a glimmer in some marketing man’s eye). My wife had just biffed her head when she crashed at the bottom of a hill and had completely forgotten about 3 miles of the ride. Thankfully, someone was sagging so they took her back to the car. I was supposed to meet them shortly since we were only about 10 miles from the car and the road was pretty fast. At the bottom of the next hill, I went to downshift and the front derailer cable split lengthwise. That stuck me in low gear on the crank which was a 22 or even a 20 (I don’t recall which). I could pedal like mad for the first 100 feet or so of the downhill and then coast until I slowed enough to get the cadence down and then grind up the next hill. It was an endless series of hills and troughs about 1/2 mile from top to top. It took close to an hour and a half to cover the distance.
I missed a curb cut at about 35mph and folded a suspension fork in half while doing a perfect Greg Louganis dismount. I pivoted on my helmet and laid straight out on the grass. I was about a mile from work and had to carry the bike back up there (precell phone) because I couldn’t get anyone to give me a ride. Unlike my wife, I never lose any time when I smack my head. I remember all the details!