Several.....
#1) Riding my brand-new, owned for six months green broken 3yo Arab gelding- bareback in the pasture with a halter and two leads (Hey, I was 18- no brains at that point). The herd took off and he went with them. No stopping. He did stop at the bottom of the hill- I didn't. Saw his ears at my knees, then forefeet by my face, then.... crunch. He did not step on me, bless him, but landed on my back, knocked the wind outta me. 33 year later my back still pops and grinds when I move.....
#2) Same Arab, 5-6 years later. Decided to go trail riding, saddled up but put my blaze orange pad over my regular pad, since it was hunting season. Away we go, hit the main trail. It's crispy out, he wants to go, so we start cantering. As we go along, my saddle starts to slip to one side, obviously I hadn't tightened it enough. I lean forward to try and fix it, he goes faster.... I lean more, he goes into high gear. The more I leaned , the faster he went. We are now flying down the trail, and I can't get my balance on the sideways saddle to stop him. I also know the path turns into an asphalt street- something I do NOT want to fall on. So, I put my arms around his neck, and leap off. When I land, I bend my knee in the wrong direction... ouch. He stops about fifteen feet away. When I hit the ground I hollered, there was a jogger down on the road and he comes up to the bridle path. I ask him to catch my horse, and he gingerly does. Not a horseman, his guy. But he did help, a lot! I fix my saddle and try and find a place to get back on- no way can I walk home, the knee doesn't want to support my weight- at all. Geym is wired, but stands long enough so I can mount, then jigs the whole mile and a half home. I manage to untack him and put him away by myself, and drive home, whereupon my mom promptly takes me to Urgent Care....
One hyperextended knee that just needs wrapped and supported. But it still gives me issues every now and then...
I've also been kicked by an Appy at a horse show, bitten a few times, came off Geym many more times with just bruises. (Went head-first into the out gate at the show ring once. THAT was interesting.) But nothing like those two stories above for major crunch times....
Friday will be 14 years since I lost my old man to colic. As many times as he crunched me, it was never deliberate and I still miss the ol' fart.