Windows: Whether you want music to play after a timer count down, to defrag after a period of idleness or to shutdown after CPU activity drops to a certain level, TimeComX offers dead-simple event management.
You won't have trouble finding tools to trigger events after a set amount of time or based on some system variable like idleness or CPU activity. TimeComX, however, is extremely simple with a polished interface. You can easily set events to occur after a countdown, after network usage drops, after inactivity, based on the time of day, and more. Set the timers or variable, select what activity you want to occur — shutdown, hibernation, running an executable, or playing a sound file are several of the options available — and then just hit the play button at the bottom of the interface. You can pause TimeComX's monitoring at any time from the system tray.
TimeComX is freeware, Windows only. Have a favourite application for easy trigger-based events? Let's hear about it in the comments.