Power Nap Daemon
PowerNap is a configurable daemon that will bring a running system to a lower power state according to a set of configuration preferences. It acts as a sort of "screensaver" for servers, watching the process table for activity rather than the keyboard or mouse. PowerNap will run $ACTION when none of $PROCESSES have executed for some number of $ABSENCE seconds. For instance, PowerNap can automatically "pm-suspend" a system if no instance of "kvm" runs for some contiguous block of "300" seconds.