Whoa There!

Process Lasso is a Windows utility that provides control over the amount of CPU various programs and processes use.

What to control can be specified by rules, such as "When any process is consuming 35% or greater of the CPU for 1.5 seconds or more and the total system CPU usage is 95% or greater, lower that process's priority until it returns to 5% CPU utilization."

Thanks to Life Hacker for the heads up.