We’re more than “halfway there.” Ten months after announcing his MSG residency, Bon Jovi will finally kick off their nine-concert ‘Forever Tour’ run at the Garden on Tuesday, July 7. The extended stay will keep the Rock Hall of Famers at the Knicks and Rangers home for nearly three weeks; their last show is scheduled to down on Sunday, July 26. If you’d like to see the ’80s hit-makers belt to the rafters, last-minute tickets are available to catch Jon, David Bryan, Tico Torres, Hugh McDonald,