Well. Reading off the inside cover of the Northside brochure, I notice a few drink specials for badge holders at popular neighborhood watering holes that don't have bands playing but sensibly got in on the Northside action: a dollar off all drinks at Iona, half-price beer and 2-for-1 well drinks at Teddy's, and a dollar off all drafts at Nita Nita. By coincidence, these are three of the very best places in Williamsburg to watch the World Cup. So if you're going to watch the game, bring your badge, and if you're going to wander around Williamsburg with your badge tomorrow, maybe dip in someplace to check out the game.
(Your other option, of course, is watch Saturday afternoon's Bands You Need to Hear showcase on the stage side of Spike Hill, and jump across to the pub side whenever the soccer crowd there gets excited enough to drown out the music.)