Everyone’s in the ‘Same Boat.’ The Zac Brown Band handed out free cruise tickets to more than 37,000 revelers at its Fenway Park show in what the country star branded “the biggest giveaway in history” worth a whopping $40 million. Brown, 48, announced the reward just before he performed the track “Same Boat” – a song he collaborated with the late “Margaritaville” artist Jimmy Buffett in 2021. “I’m buying every single person here a cruise for two people on the boat,” the Atlanta-born singer told the legion of fans that had packed into the famous ballpark — home to the Boston Red Sox, NBC10 reported. “This is the biggest giveaway in…