There were some hurt feelings and more than a few complaints on message boards when a billboard featuring USC quarterback Matt Barkley popped up a few blocks from UCLA's campus a week ago, adding a new chapter to the schools' LA rivalry. Now, it's become a mystery: The billboard, carrying the slogan "We Play To Finish," has suddenly vanished. No one is taking the credit (or the blame) for its disappearance. Both schools denied having anything to do with the situation. Was it taken down legitimately or vandalized? And for sheer nerve, does this exceed the "Blueprint for Greatness" billboard featuring Nets owner Mikhail Prokhorov and Jay-Z that emerged next to Madison Square Garden in 2010?