AC/DC welcomed a special guest onstage for the final show of their Power Up Tour. During their concert Friday (Oct. 2) at New Jersey's MetLife Stadium, the iconic Australian rockers brought out Dave Grohl to join them for "Highway to Hell." "Hey everybody, we got something to tell you. You better listen up close now. A very good friend of ours asked us today if he could come up and join us on the stage for 'Highway for Hell.' And we said, 'Yes Dave, you can.' David Grohl!" AC/DC's Brian Johnson told the roaring audience as he hugged the Foo...