To me, 'Gospel' (along with the sentiments and terminology usually associated with it) is one of the main concepts that has become ossified among Christ's followers over the years. Largely for that reason calls to believe the Gospel are no longer terribly effective in inciting people to follow Jesus of Nazareth. 'Good News' is not far behind.
Fortunately, scholar Tom Wright has posted this video (which I borrowed from the 'Near Emmaus' blog who got it from Vimeo who got it from Evangelical Alliance) that shakes loose some of the shards of ossification.
Tom Wright on What the Gospel Is