Probably a tie ...
We were snorkeling at Point of Rocks on Siesta Key, and I was giving my 9 yo DS a big safety spiel about being careful of cutting himself on sharp rocks, when, you guessed it, I cut myself on a sharp rock. Put a 3 inch lateral gash in my right knee, and didn't notice it until people near me started freaking out about blood in the water. (I have a scar from that one to remind me.)
The other happened some years previously, not long after we got married. I decided to surprise my DH and hop into the shower with him. He was washing his hair at the time, and he spun around, startled, without lowering his arms. He caught me right across the bridge of the nose with his elbow and blackened both my eyes. I had a lovely time explaining to several medical personnel that yes, DH had done it, but no, I didn't need domestic violence assistance! (To make matters worse, a couple of years later when DS was an infant, he managed to break my nose by throwing his head back really hard. That also blacked both my eyes, and the same group of doctors were again skeptical when I told them that this time the baby had done it.)