The year 2013 marks a major milestone for Australian rockers AC/DC.  The group will celebrate four decades since they first called themselves a band.  The hard-rocking group may also be working on plans to celebrate their upcoming ruby anniversary in a way that will rival the success of their last album, Black Ice, and the nearly two-year world tour that followed.  Considering the fact that the Black Ice tour was the third highest-grossing concert tour of all time, it will literally be a hard act to follow.  Guitarist Angus Young recently reported that he and his band mates were thinking about recording a follow-up to Black Ice and again hitting the road.  AC/DC fans unite!