First fall: Riding a friend's Arab by myself on the trails. There was a tree that had fallen across the path and the only way was over. It was forked, so you had to step over two sections -easy in theory- but this horse decided it was destined for the Olympics and launched herself over that tree like her life depended on it. I ride Western and I remember coming about six inches out of the saddle, wishing I had shorter stirrups, and then coming down crooked and sliding off. I had burns on three fingers from holding the reins (I had no intention of walking back to the barn) and bruises on my arm, leg, and wrist, but was pretty much unharmed.
Worst fall: Never really had one bad fall, but I had a series of three in one week that kind of compounded on each other... My green broke mare has a 0-30 MPH spook and, needless to say, I was in the roundpen riding bareback and she took off. I slid right off the second she took the turn. I don't even remember how I landed because I was up so fast. Two days later she bolts and my cinch breaks. I feel my saddle going over one side and thought it was the horse falling on top of me. Hid the ground and lay there going... No way that just happened, rolled over, got up, and chased down my horse. THEN, that weekend, my cousin was over and we were feeling particularly bold, so we decided to get her used to being rode bareback. I get on first, and my cousin goes to get on second. Gets her foot in the stirrup, grabs ahold of the saddle and tries to swing her other leg over... and gets stuck. Oops... Horse goes sideways, she holds on, horse goes forwards, she goes back, I go sideways. Pick ourselves up laughing, me a little slower than I would have earlier in the week. Fast forward a week, chiropractor is giving me the "you've lost your mind look" as he tells me I have at least five displaced ribs, but I need x-rays, to which I told him I was not getting x-rays because I have no intention of knowing how bad things really are. Now, two months later, I've managed to get down to 3 displaced ribs, and I can finally bend over sideways... sorta :P