Calendar Man

If you haven't visited Chris J. Miller's Unauthorized Chronology of the DC Universe, now's a great time to start. He's put together an exhaustive timeline of DC history, from the birth of the Source to multiple versions of the 30th Century and beyond. Now that Infinite Crisis has ended, he's even compiled a day-by-day account of the cataclysmic events.

As might be expected, given the current nature of DC's continuity, the site won't be updated for at least the next year, but there's so much to explore, it may well take you that long to get through it. Of course, by then history may be entirely different....