At my most recent art fair, my booth was on the street, right up against the curb. I have my chair at the back of my tent behind tables. It was getting sunny, so I decided to scoot my chair up a bit. Apparently when I moved it, I managed to get the back legs right at the crack between the blacktop and the cement gutter.
When I sat back down, I just ... kept ... going. I ended up falling straight back, shade umbrella and all. Nothing was hurt but my dignity, luckily.
Of course, I couldn't be the least bit subtle about it; I screamed all the way down. People came running from all over to make sure I was OK which was really nice but that much more embarrassing.
I did win an Award for Excellence which I'm pretty sure was for my 3D glass mosaics vs. my performance.