A few times. I've had to catch a bus on two occassions...when I broke a pedal and when I broke a crank.
I had to carry a bike about a mile back to work when I slammed into a curve at about 30 mph...missed a corner...and folded the fork under. I did a full layout dismount with a pivot on my head. I had to carry my broken bike back up to work so that I could call home. Pre-cell phone days