Over the weekend the load average on my server leaped from an average of 0.5 to 15, and got pinned there. The culprit was miniserv.pl. A dozen instances of this were running at 100% cpu usage. I changed the user password and killed all their instances of miniserv.pl, and life went back to normal for the server. Even during the peak of the problem, the server was still able to deliver email and web content without any noticable slowness.
It turns out that the user left an instance of webmail running on a computer the kid was playing on, and then tried to launch multiple usermin windows from another computer, which were not letting him in. Most of these were running at almost 100% cpu capacity. He was on a MacIntosh logging in with Safari. Any reason why these were running at such a high CPU utilization? Such a comedy of errors, I was on the server at the same time killing his windows, thinking I was under a DOS attack, thinking what a silly way for someone to try tying up my server!