The most spectacular strike to the 'nads that I have ever received happened when I was competing in the West Coast Tae Kwon Do National Qualifier in Oregon state. In this scenario, I was engaged with my opponent in the first round, and we were wearing standard sparring gear (foam/cloth limb pads, helmet, hard-surface Hogu (chest piece), mouthguard, and of course cup). With about thirty seconds to go in the first round, I went for a roundhouse kick to my opponent's head (which was at about a 6' elevation) - at the same moment he went for a full-power back kick, which was roughly at a 3.5' elevation.
His heel made contact with my cup, then my genitals, then likely my pelvis, as I flew a few feet through the air, landing on my back at the edge of the ring. Not, at this point I was surging with adrenaline, so all I had felt was the bemusement and slight outrage of being knocked down by a spectacular nutshot. The referee rushed over as I sprang back to my feet, eager to get back into it. He insisted on giving me a 10-count, making sure three times that I was still willing to continue.
Mind, I didn't FEEL anything wrong at that point, minus a curious pressure in my nethers.
I actually managed to finish the third round, losing by 3 points. Breathing hard and excited, I exited the ring, sitting down for a breather. At this point, I noticed that the pressure had developed into a considerable throbbing ache. And no matter what position I assumed (standing, sitting, prone, doubled over) it did not get any better.
It took me about ten minutes to shuffle off the competition floor and to the dressing room (a minute-and-a-half walk, tops), grimacing and sweating, as I tried to pry off the offending cup that had both helped and hindered me.
I probably sat in a white-pain daze for a few minutes, breathing and wondering if I'd ever felt anything quite like this before.
Within the hour, we were on our way back to Washington state, and I was paralyzed in the passenger seat - unwilling to move or even shift position, else the considerable dull pain would change to agonizing sharp pain.
Amazingly, no hospital attention was required. There was no freakish swelling, clots, or long term damage (at least as far as I know - this was three years ago). I could not walk for two more days, however, and the following week was extremely awkward for me... You see, it is as if I possessed a painful pendulum between my thighs, and if it touched either one (or any other matter, in fact), it's as if I were playing Operation. Naturally, there was call for me to 'walk it off' and stop pretending, but I tell you now, that by far the most painful scrotal injury I had ever sustained.
...
The most comical would have to be when I was thirteen and slipped from a river-crossing rail-bridge's middle support column, falling six feet onto a log that had been piled at its base among the flotsam on the sandbar. That was just pure comedy. True, I couldn't breathe for almost a minute, but I laughed as I limped home. Taught me to be careful when climbing where I shouldn't be...