We picked Bloomington because of friends. A couple we'd been close with in New York moved there four years ago when she got a professorship at IU. We wanted to see them. They didn't have an agenda for the day, so I pulled up the Atlas Obscura app and suggested two places: the Slocum Mechanical Puzzle Collection and the Captain Janeway statue . They'd never heard of either. Four years in Bloomington, and they didn't know their town held more than 30,000 antique puzzles or a bronze monument to a starship captain who won't be born for another three centuries. At Slocum, my kids worked through nearly every puzzle on display in the room—wooden geometries, trick boxes, ancient sliding-tile puzzles. My husband, the family brainiac, got stuck on one called Chinese Rings: six interlocking metal rings threaded onto a U-shaped wire loop. The goal is to remove all the rings, then replace them. It looks simple—just slide them off. But the wires block your way. You can't take them off one at a time.…