The quirkiest restaurant in Tribeca (and possibly the U.S.A.), the subterranean Ninja is designed to replicate the experience of visiting a “ninja castle” of Japan’s feudal days: The layout is a warren of rooms, and ninja-waiters appear from myriad secret passages. The food is generally Japanese—the signature dish is surf and turf with risotto—and not generally the point. This is theater, complete with the opportunity to buy themed merchandise. Kids love it, but the thrills don’t come cheap.