And then, suddenly, nothing happened.

The history of the world is a large subject, covering something over four billion years.  However, complex life forms only arose about 500 million years ago, at the start of what is now called the Cambrian Period.  Before that?

Well, the International Commission on Stratigraphy has divided the preceding 3.5 billion years into several sections, separated more or less arbitrarily into large chunks of time.  From the creation of the Earth until the lithosphere settled down is the Hadean Eon, for example.  Then there's the Archean Eon (divided into four eras), and the Proterozoic Eon, divided into three Eras, each of which is further divided into three or four Periods (unless they go into overtime).  The kicker?  Of these 20 or so Pre-Cambrian official designations, only one or two of them are even vaguely interesting.

They're all mostly just too old-- hardly anything survives from that part of history.  There are a few rock outcroppings here and there that date all the way back, and some fossil-y sort of things from ancient bacteria and algae, but that's about it.  So if someone jumps out at you in a dark alley and demands to know three interesting things about the Orosirian Period, you can take some comfort in the fact that you'll know it's a trick question.  There were only two.