Rapper Snoop Dogg has been hitting the studio with a surprising collaborator, former "Two and a Half Men" star Charlie Sheen.  The troubled actor posted a picture on Twitter Tuesday of himself, Snoop, and Robert Patterson, a former member of Korn.  Sheen's Tweet which he linked to the photo read:  "Warlock meets his makers-music makers that is @SnoopDogg @robpatterson666 get ready to rock the Sheenius within! http://twitpic.com/4d9cw1"