Yes, I have been in a fight. Years ago, at a college in Louisiana, I was walking on a trail in the park (the university was large, and had its own park) at about 10 pm. It was a nice, slightly chilly day, and I was talking to a friend on my inexpensive cell phone (one of those crappy flip phones). A young man, about my age, walked past me on the trail - then turned and punched the back of my head. Surprised, I fell and my phone flew out of my hand. He tried to pin me, but after a brief struggle, I was able to wrestle him off. Without a word, he then ran off into the darkness of the night. Besides a minor nose bleed, I was fine. Why he attacked me, I have no idea. I had nothing of value on me; no wallet, cheap clothes, and an inexpensive phone. We'd never talked or met each other before, so it seemed like such a random and useless attack. Best part? My phone stayed on even when I dropped it, so my friend heard the entire thing. That must have been pretty scary to listen to.
Moral of the story: You can get jumped at anytime, for any dumb reason. Try and stay with friends in well-lit areas, and carry some pepper spray or a pocket knife. You never know when you'll need it.