Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
NetTime - nettime is a time & attendance software solution.
AlarmDJ - Online Alarm Clock - Use YouTube videos or MP3 files as alarm sound. Works offline.
Meinberg NTP - NTP client and server download for different operating systems.
Free Alarm Clock - Free Alarm Clock is a free, full-featured and user-friendly computer alarm clock for Windows.
Atomic Clock Sync - download the free atomic clock sync config utility to optimize how your Windows pc receives updates from time servers