So a while back when I started my training, I was going out to the airplane to preflight. I was at a new school, and unfamiliar with their procedures at the time, so when I went up to the airplane, I pulled out the chocks.

I hopped into the airplane and, head down, started writing down the times, checking for certificates, etc. It was then that I felt myself strangely surging forward, and my heart skipped a beat. I knew what was happening, and couldn't believe my own stupidity. I looked out the window to see that, sure enough, the airplane was rolling backwards across the ramp! I frantically reached under the yoke and pulled the parking break to full, bringing the airplane to an abrupt stop, but not before it had traveled twenty or so feet behind the lines it was parked on and almost rolled down a grass embankment about 30 feet from the tower.

I was almost certain somebody had seen what happened, and my @$$ was grass. I hopped out of the cockpit, preparing for the worst, but all I saw was a flight instructor - oblivious to the whole thing - standing out on the ramp and having a smoke.

Worried that he would look over and realize the blatant asymmetry in the aircraft lineup, I continued to perform the quickest preflight ever, but will never forget that crazy incident that (fortunately) never resulted in any damage being done to the airplane.