Generations

Western, mostly US-centric http://en.wikipedia.org/wiki/Generations_%28book%29#List_of_Generations

Late Medieval

1433 - 1460
1461 - 1482

Reformation

1483 - 1511
1512 - 1540
1541 - 1565
1566 - 1587

New World

1588 - 1617
1618 - 1647
1648 - 1673
1674 - 1700

Revolutionary

1701 - 1723
1724 - 1741
1742 - 1766
1767 - 1791

Civil War

1792 - 1821
1822 - 1842
1843 - 1859

Great Power

1860 - 1882
1883 - 1900
1925 - 1942

Millennial

1943 - 1960
1961 - 1981
1982 - 2003
2004 - 2025