A couple concussions from football and a lower back injury from deadlifting too much. Why did I do it? Don't really know. I'd never lifted as much as I was attempting to.
I tried to lift it and felt a pop in my lower back. It didn't hurt at first, but the pain soon set in and I was having a hard time moving. Basically, any bending was out of the question, and forget about sitting. Went to the nurse's office and called my dad who came down and brought me to the ER on the base. Thankfully I didn't do major damage, but I was clearly in bad shape.
What really sucked was that I had a competition to attend for the ROTC unit I was in, in addition to pole vaulting for track and field. I recovered enough to compete in both, but I didn't reach 100% until a few months later. Lots of yoga. Oh, and I used to ice it until I tried to do it one day and it hurt like hell.
There's also a small scar above my left eye. It's unnoticeable since it's small and covered by my eyebrow. Got that from taking a knee to the head during a wrestling match.