Editor: iTime is a free Macintosh system extension that places a metric / Internet time clock in your menu bar.
With metric time, or Internet time, each day is divided into 1,000 beats rather than into hours, minutes, and seconds. iTime supports three time zones:
Internet time, based on Biel Mean Time (BMT); universal metric time, based on Greenwich Mean Time (GMT); and local metric time, based on your local time zone. With a metric time system, beat 000 corresponds to 12:00AM Midnight, the start of the day. A complete metric time system also simplifies date keeping since the year is no longer divided into months and weeks; the year begins on day 000 and ends after day 364 or 365, depending on whether the year is a leap year or not.