My Time Wizard
If you use MyTimeWizard your computer clock will permanently stay in sync with an atomic clock. The atomic clocks are the base for most accurate time measurements available. You will now have the chance of taking your computer clock as a reference for all clocks in the house. ... You won't even have to check the time as MyTimeWizard even warns you about your schedule by making use of events.
http://www.racsoftware.com/downloads/timewizard.exe - 2Mb - Download - Screenshot

Atomic PC Clock
Atomic PC Clock allows you to synchronize your personal computer with the National Institute of Standards and Technology atomic time servers, ensuring you always have your local time accurately listed on your computer. It also offers two different types of monthly calendars and an intuitive user... Monitor exact time on your PC: Atomic PC Clock will synchronize with atomic time servers at specified intervals, so you do not need to manually check the accuracy of the system time on your computer every hour.
http://www.atomicpcclock.com/atomicclock.exe - 656Kb - Download - Screenshot

Chronos Atomic Clock Synchronizer
Chronos Atomic Clock Synchronizer is a utility for people who need their computers to use exact time. The program connects to various atomic clock timeservers and synchronizes your internal clock with time provided by these servers. Key benefits: connects on many atomic clock time servers; you... Some other features: starts up automatically minimized to the tray; updated server list; shorter latency time for synchronizing; faster connection to the sync servers. ... 1 seconds.
http://www.aresgalaxyonline.com/downloads/chronos_setup.exe - 761Kb - Download - Screenshot

#1 Atomic Clock
Atomic Clock lets you synchronize your computer's clock with any Internet atomic clock (time server). It uses a high-precision network time protocol (NTP) which provides accuracy of several milliseconds depending on the characteristics of the synchronization source and network paths. ... Features: Skinned, Work as Time Server, Synchronize Periods, Import Time Servers List!
http://www.freefileszone.com/atomic-clock/download/acdemo.exe - 488Kb - Download - Screenshot

Atomic Alarm Clock
Alert yourself about important events with different alarms and replace your Windows tray clock using different skins. Computer alarm clock that will play a MP3 file. It also can run a program, log off, reboot, shut down, or power off. Atomic Alarm Clock also an atomic-time synchronizer and... This computer alarm clock is built into your personal PC and is completely customizable. ... Nice Computer Alarm Clock! ... Support Longhorn clock style. ... See the time, seconds, day, date and system UpTime in different skins.
http://www.drive-software.com/download/ataclock.zip - 1Mb - Download - Screenshot

On-Time Atomic Clock Sync
Synchronize your PC's clock with internet atomic clock servers
http://calendarconstructer.com/on_time_atomic_clock_sync.exe - 420Kb - Download - Screenshot

Attache Transparent Clock
Transparent desktop clock with fully customizable shape, alarms, and atomic time. It may have a digital or analog clock face of various colors, sizes and shapes - you may even set individual parameters for each application you run, so that the clock were clearly visible in any environment. ... This state-of-the-art piece of software may be used as a beautiful replacement for standard Windows digital clock or as an alarm-clock/reminder, to help you stop forgetting your friends' birthdays and other important but not so easy to memorize events.
http://www.softdemon.com/attclock.zip - 1Mb - Download - Screenshot

GPS Time and Test
It is a PC Clock synchronization program. The program synchronizes a PC Clock to the right time using artificial satellites. It is alternative solution to synchronizing with atomic clock using NTP(SNTP) and Internet. The program works in the interactive mode or in background. ... The product is free for users of BrigSoft products Atomic Clock Service, PC Atomic Sync and OS Non-Proxy Atomic Sync. ... Default protocol version is NMEA 0183. ... It outputs a port receiving buffer, extracts all NMEA sentences and counts check sum errors.
http://www.brigsoft.com/atomic-clock-sync/download/GpsTimeInst.exe - 447Kb - Download - Screenshot

2D_Gold_Clock Screensaver
Synchronize your local PC time using the Atomic Clock servers. Collection of various analog clock with synchronization your local PC time using the Internet(Uses the National Institute of Standards and Technology (NIST) Atomic Clock servers). Choosing various dial, various arrows, choosing... The most different variants of clock on every day! ... Having switched on a casual choice you receive new clock at each start.
http://www.all-sweets.com/download/2d_gold_clock.exe - 468Kb - Download - Screenshot

The Time Machine
Professional looking clocks, skinable calendar, atomic synchronizer and organizer. The Time Machine is a massive set of components and functions, completely covering all the tasks of managing your computer clocks. That includes managing appearance of clocks, display of various time zones,... - Highly customizable digital and analog clocks with a powerful skin engine; - Integration of the clocks in a Windows environment.
http://www.atlantsoft.com/utils/store/ttmsetup.zip - 4Mb - Download - Screenshot