Geez, compared to some of these, mine is pretty tame.
In a 75-mile charity ride last summer, I was in a pack of riders -- some experienced, some not. The guy in front of me was trying to get everyone formed up into a double paceline, but only about half of us knew what he meant. The guy in front of him was all over the map speedwise -- he'd be up over 20 mph, then would fall off to 17 or so. Then we hit some rough pavement and the idiot slams on the brakes. The rider in front of me ran into his pedal and fell (the guy who'd slammed on the brakes didn't go down).
I had folks on either side of me, although I doubt I could have gotten around him if I'd had the room. I remember thinking, "This isn't going to be good..." as I ran into him and did a classic endo. I landed on my shoulder and rolled, and was extremely lucky not to break anything -- except for the gel packs in my back pockets.
No sooner had I hit the pavement than a cute young thing fell onto me. Usually, I'd enjoy rolling around, bare legs all tangled, with a cute young thing, but not this time. We got ourselves untangled, collected our wits, then got our bikes untangled. Her bike and mine were rideable, so we collected our water bottles, etc., which had scattered from hell to breakfast and got ready to continue.
The first guy who went down wasn't as lucky. His front wheel was all out of true, so he had to SAG to the next stop, where a bike mechanic trued his wheel for him.
I came out of it with some road rash, a ripped jersey, and bruises. My bike was in pretty good shape, except my seat was ripped up pretty badly.
The worst part was that the idiot that caused the whole thing rode on as if nothing had happened.