Well, here's more pertinent information: badges are on sale now for the four-day festival, from June 16-19 at various Williamsburg and Greenpoint venues, including McCarren Park, where Beirut will play in a new 5,000 capacity outdoor venue on June 17.
You can get badges for $60, and tickets to Beirut's show here. Badges grant access on a first-come, first-served basis, in addition to all Northside ideas, art and film events. You can also get discounts at bars and restaurants. So it pretty much sounds like a no-brainer if you want to take advantage.