Coming down a hill going almost 30, didn't notice a set of deep train tracks crossing the road at about a 45 degree angle. Went over the handlebars into some gravel, which I picked out of my hands and elbows for about an hour that night. I'm pretty sure I saw my bone where the flesh is thin near the elbow. It could have been worse, though, because some part of my bike (rear rack, I think) came whipping down on top of me because my feet were still in the clips, cracking my helmet.