Zac Brown Band not only gives fans the show of a lifetime with 15 sold-out concerts at Fenway Park, but now the group's giving them the trip of a lifetime, too.

Zac Brown Band not only gives fans the show of a lifetime with 15 sold-out concerts at Fenway Park, but now the group's giving them the trip of a lifetime, too. During the band's 15th consecutive sold-out show, Zac Brown surprised more than 37,000 fans by giving everyone in attendance a free cruise…