40 years ago - in a tired Cessna 140, on a 6000' runway -
At about 50' altitude the cowl popped open, due to a faulty latch. I had at least 4000' runway left ahead of me, and no desire to burn up an engine in the pattern, so it was an easy choice to close the throttle and land straight ahead. IIRC I slipped a bit to try to close the cowl to help visibility.
No harm done except to my self-esteem for accepting marginal hardware on preflight.
But I still had power as long as I kept CHT under redline. If it had happened at 500' I could have flown a tight pattern at part power, I guess, with similar outcome...