A week-long summer scavenger hunt across the Minuteman Library Network: pick up a free passport at any participating library, then visit libraries across Greater Boston on their featured crawl days, find each library's hidden clue, and collect stamps. Completed passports enter a grand-prize drawing. Around two dozen libraries take part, from Arlington and Watertown to Natick, Needham and Newton — a free, all-ages tradition that turns library-hopping into a family road trip.