Come on, nothing beats "long time ago".
Ok, seriously, the CHinese use the stem-branch system.
A year is a branch - they are named after animals like I said before.
A cycle is a full twelve years, and there are ten stems, named after five elements, each with a "yin" and a "yang" (Wood, Earth etc...)
The year of 2005 is the year of the Wooden Rooster (also called the Green Rooster).
Cycles are then numbered I guess. 2005 is the 4702nd Chinese year.