Our calendar is not perfect, which is why we have leap years and leap seconds. While our New Year started on January 1, 2009 at 00:00:01, other calendars had a different take on this moment in time:
| Julian Day | 2454832.500011574 |
| Julian Calendar | 2008 December 19 |
| Hebrew Calendar | 5768 Teveth 5 |
| Islamic Calendar | 1430 Muharram 4 |
| Persian Calendar | 1387 Dey 12 |
| Mayan Long Count Calendar | 12.19.15.17.10 |
| Indian Civil Calendar | 1930 Pausa 11 |
| French Republican Calendar | Year 217 |
| ISO-8601 | 2009-W01-4 |
| Unix Epoch | 1230768001 |
| Excel Serial Day Number | 39814.00001157401 |
| 1904 Date System (Macintosh) | 38352.00001157401 |
Fourmilab Switzerland has More on these Dates
Plus Wikipedia lists lots and lots more calendars.