Rob Gronkowski has a book, a cruise, and a SuperDrink. As of this week, he also has a ball. It was announced Wednesday that the inaugural Gronk Gala, which will benefit the Gronk Nation Youth Foundation, will be held April 14 at Mercedes-Benz of Burlington. The black-tie affair will feature Burlington restaurants, entertainment, and an auction. The Gronk Nation Youth Foundation supports local sports programs. Tickets are $522.95.