Well, I've had the usual rounds of getting kicked, nutchecked, and so on, but there are two incidents that stand out. The first is a fairly traditional example of pain putting me into a fetal position. some time in either my senior or junior year of highschool, I hand stitched a sand filled hacky sack, because the things were impossible to find where I lived, and I wasn't about to pay $10 or more for a bag of sand from the internet. well, it was and still is a great hacky sack. It's roughly the size of a golfball, which is standard for freestyle bags, and it's floppy enough that stalling is actually possible, without being so floppy that it's not round. One day, when it had been raining, I had a nice circle going with the hacky sack. It laned in a puddle, which didn't stop us from playing with it, but did increase the weight by an order of magnitude. Well, the sack gets kicked to this one guy who kicks it up a few times, and then roundhouse kicks the sack...
I was curled up in a fetal position for quite a while, and it remains to this day the worst blunt testicular trauma I've ever experienced. But that's not the worst thing that ever happened to my genitals.
At this point, your probably wondering what could possibly be worse than having a golfball sized implement smashed against your balls at nearly the speed of sound. Well, it's simple; being bitten on the balls by a mosquito. One night several years ago, I went to bed with a mosquito somewhere in the room. During the course of the night, the bloody thing managed to crawl up my shorts and bite me right on the balls. If you think your balls itch normally, try having a mosquito bite them. Or better yet, don't. It itched for days, and of course I managed to break the skin scratching it, so that had to heal too. Moral of the story: always make sure that there is no way for any mosquitoes in the area to get to your balls,
before you go to bed. You'll thank yourself later.