It's time for a little R and R for the president and his family as Barack Obama begins a 10-day visit to Martha's Vineyard on Thursday. The Obamas vacationed on the Massachusetts island last year as well. The White House knows that anything can happen when the boss is away: it was over Christmas, while Obama was in Hawaii, that the underwear bomber tried to blow up a plane over Detroit. Obama aides say the trip is really a working vacation. "He'll continue to get his daily intelligence brief from John Brennan, who will be there. He'll be getting constant updates on what's happening the economy and other issues," a spokesman said. Vacations are a thorny problem for every president, and Obama has gotten heat in the past for being at play while the American economy suffers and wars wage abroad.