The Games of the XXX Olympiad are already underway in London, even though the torch won't be lit until Friday evening. This year, we'll be watching basketball, swimming, track, gymnastics, and all of the other summer events and when it's all over, we'll have a new set of memories and favorite moments for the ages.

Just in time for the London Olympics is this new viewer's handbook, which gives a brief history of the Games and explains all of the trivia and traditions. Exactly how wide is that balance beam? Why does Greece always march first in the Opening Ceremonies? What do the five Olympic rings and their colors symbolize? It's all here, along with "top ten" lists, rules, historical backgrounds, and what not to miss over the next few weeks. The eyes of the world will be on London -- see here for schedules and headlines. Let the Games begin!