The earliest brain fade moment I remember was back in my BMX days. I was riding with friends through a narrow dirt trail in the trees and brush along the river. In places, you had to really concentrate to make it through the trees without bouncing. I quickly discovered that the handlebars on my Redline were wider than the bars on my friend's Hutch, Mongoose, and Kuwahara. I aced an "insta-stop" when my bar ends each caught a tree alongside the trail. I went into and over the bars... and I swear it felt like three days before I regained my breath.
Strangest thing the ever happened was on my DX-5000. One of my smart-arsed friends decided it would be cute if he messed with my rear wheel alignment screws. Of course, I didn't realize he had done this so I shot down my parents driveway, around the cul-de-sac and started building speed down the street. Right about the time I got in front of my parent's house the rear wheel sort of wedged itself in and from there on it got a bit fuzzy. I remember the cranks stopping which caused me to lunge up over the bars. Literally, the next thing I remember is landing on both feet with the bike landing in front of me on the rear wheel in a vertical fashion... I had my hands on the bars. I check myself out and I am literally unharmed. Even more amazingly the bike didn't have a mark on it either. I half thought I was dreaming or losing my mind before I even made it to my 15th birthday but at that moment a neighbor lady came running up to me all worried and asking if I was ok. She had been sun bathing on the side of her house and said she saw me "flip all the way over" and thought for sure I'd be hurt. I still can't visualize that one in my head... wish I remembered more of it though!