Activision has announced that the Guitar Hero franchise has officially earned one billion dollars. Furthermore, the franchise has achieved this feat in just over two years -- 26 months to be exact -- selling in excess of 14 million units across the many iterations of the series. Activision adds that Guitar Hero III was the number one title of 2007 and that it has become "the best-selling video game of all time in a single calendar year." So, we're guessing it sold a lot of copies. Finally, 5 million songs have been downloaded for the game, which ain't too shabby (just ask the Rock Band folks). Somehow, we get the feeling that Activision is happy they bought Red Octane.