XKCD Presents
EARTH STANDARD TIME
(EST)
A Universal Calendar for a Universal Planet
EST is...
Simple * Clearly Defined * Unambiguous
Free of Historical Baggage * Compatible with Old Units
Precisely Synced with the Solar Cycle * Free of Leap Years
Intermittently Amenable to Date Math

UNITS
Second: 1 S.I. Second
Minute: 60 seconds
Hour: 60 minutes
Day: 1444 minutes (24 hours 4 minutes)

Month: 30 Days
Year: 12 months

RULES
For 4 hours after every full moon, run clocks backward.
The non-prime-numbered minutes of the first full non-reversed hour after a solstice or equinox happen twice.

[Epoch]      
00:00:00 EST, January 1, 1970 = 00:00:00 GMT, January 1, 1970 (Julian calendar)
[Tim Zones]
The two EST time zones are 
EST
 and 
EST (United Kingdom)
. These are the same except that the UK second is 0.944 standard seconds.

Daylight saving: Countries may enter DST, but no time may pass there.
Narnian Time: Synchronized✓
Year Zero: EST 
does
 have a year 0. (However, there is no 1958.)
{{Title text: The month names are the same, except that the fourth month only has the name 'April' in even-numbered years, and is otherwise unnamed.}}