I haven't had too many "strange" things happen, but back in 1983, I encountered a car that pulled out of a Wendys, and then they decided they needed to pull back in NOW.
I was going about 45, had to lock up the brakes, and slid into their path. The bike hit the front of the car, went up on the hood, busted their windshield, and launched me about 30 feet through the air across their car.
Flying wasn't bad, but the landing sucked ass. The bike was a loss, I had a broken elbow, and got an ambulance ride. My full-face helmet saved my life as my head and left shoulder was the initial landing point.
To this day, I cringe a bit when I see a turn signal of a "left turner".
Not strange, but one of the worst road hazards I've seen/hit.
Oh yeah...When I was about 13 years old, I had a wasp fly into my helmet going down the street. I freaked out, ran the trail bike into the ditch, got the helmet off, and believe it or not, I never got stung. It was freaky feeling him crawling around inside the helmet.