ASD Clock is a Free, Open Source Windows clock replacement. It's super customizable, comes with a great Alarm Management system, has Atomic Clock, clock labels customizations and even an Alarm Synchronization tool which can be used to sync multiple installations. You can use ASD Clock to shut down your computer at a certain time or even start or stop programs. The alarms can be repetitive, countdown or even repetitive countdown. The appearance of the alarms can be customized in the most complex of details, using window animations, fade-ins, slide-ins and even the sound of the alarm can be fully customized (custom mp3 or wav, numbers of repetitions and distance between repetitions).