I would like to see CPU Limit (
http://cpulimit.sourceforge.net/) become a member of the Ports Collection. It's a small command line app which throttles CPU usage of specific applications. This helps prevent the system from getting bogged down.
Originally CPU Limit was written for Linux, but I've managed to get it to compile on FreeBSD. I'm attaching the patches required to get CPU Limit to compile and run on FreeBSD/PC-BSD.
CPU Limit
Threaded Mode