The billionth game of Halo 3 was played last Saturday. Bungie then calculated the play time of every online match - not counting custom maps - and it reaches 2,023,153,340,764 seconds, which equals out to roughly 64,000 years.
To further drive home the point of how huge of a number that is, they mentioned that 64,000 years ago neanderthal walked the Earth and modern man hadn't yet set foot in Asia.
Some guy in the comments went on to speculate that a low-ball estimate of World of Warcraft gameplay was up around 750,000 years. Either way, I'm crying. And not because we haven't cured cancer either it's just that *sniff* I'm so damn proud of you guys.
Thanks to Mark, who contributed not one but 10,000 of those years.