I was Riding trails at ourimbah during the week with my mate. He was Infront and we're going up this medium hill that runs along a fence line. I thought I was doing good until all of a sudden I'm on the ground. I open my eyes and my vision is all messed up for maybe 10 seconds. It reminds me of diving the Coolidge in Vanuatu at 70 meters and being narced off my head. I sit up and don't remember where I am or how I got there. I work out I'm out riding but not sure which hill I'm on. I'm not sure who I'm riding with either. A few minutes pass and Adam turns around and asks if I'm ok. I say no and that I need to sit down for a while. My helmet doesn't have any major damage. I eventually ask him to ride my bike up the tough section and we slowly ride back to the car park. I slowly start to remember things and I can vaguely remember hitting my head. That helmet the best $30 I ever spent in my life. Anyone else had a stack that knocked them out?