There are also the technological
Five Ages. I find it amusing and perhaps somewhat frightening that sixty years ago, there were only three
The Stone Age -- Humans used stone tools to hunt and prepare their foods.
The Bronze Age -- Humans began to use weapons and other tools made out of bronze. Primitive machines began to appear.
The Iron Age -- The latter portion of which was called the Industrial Age. Here we begin to see use of sophisticated machines, thanks to the strength and flexibility of iron and steel.
The Space Age -- The leaps in technology necessary to raise ourselves from the surface of the world sparked development in all branches of the sciences. Everyone thought, at the time, that the Space Age was going to last forever, and be the focal point of the human species, as we followed our manifest destiny to the stars. Until, that is, some boffins at DARPA started really playing around with those overblown calculators called computers...
The Information Age -- Part hype, part technology, part wishful thinking. The age I find myself in, as an adult, where instantaneous planetwide communication is considered typical (and even tedious) rather than a miracle. Based around the wonder tool, the computer, the Information Age is a drawing-together of humanity. And I'm starting to sound a bit like John Katz, so I'm going to shut the hell up now.
Consider: Here, in the Information Age, I stand with a Mexican burrito in one hand, and a Chinese egg roll in the other, sipping Coca-cola. A hundred years ago, this meal would have been impossible. Truly, these are enlightened times in which we live.