This evening, at sundown, the Jewish New Year of 5766 begins. The holiday marks the 5,766th year since the creation of Adam and Eve. The specific date is calculated by making use of the biblical data tracing the complete geneology of the decendants of Adam provided by the "begats" in Genesis, as in the snippet sample listed below:
And Salah lived thirty years, and begat Eber:
And Eber lived four and thirty years, and begat Peleg:
And Peleg lived thirty years, and begat Reu:
And Reu lived two and thirty years, and begat Serug:
And Serug lived thirty years, and begat Nahor:
So we can easily figure out that it was 156 years between the birth of Salah until the birth of his great-great-grandson Nahor. See. And you never knew why those Biblical begats were there.
In any case, Happy Jewish New Year!