A few times here and there.

Firstly as others have mentioned. Just sibling. My younger brother and I had our moments where occasionally we would get into fights. Nothing super serious, though one time he got a good hit on me and knocked out one of my loose teeth at the time xD.

Second and last notable one I can remember was in 2nd grade. One of my classmates jumped me and started beating me up. I personally don't remember it at all, but my family and friends still tell me about it. In fact, it's how I made one of my friends because he stood up to him and knocked the guy off me. My parents had to step in and try to defend him so he didn't get suspended or expelled for helping me. Oh and fun fact, he guy who was beating me up, we became friends sometime after that.

Other than those, there really weren't any fights. I've helped prevent some throughout high school. One was where someone literally picked up a Cymbals in the band room and threatened someone with it. Both of them being close friends =x