Best virtual art gallery

There's nothing quite like free art that doesn't require following the social norms of viewing it while inside a swanky museum. From September 13 through October 31, all you need to do is saunter down to Broadway between 21st and Ninth streets with a smartphone or tablet, download the Augmented Reality app, and voilà: virtual public art will appear when you hold up your smart device. The art is multimedia, and includes “two-dimensional” wall murals on buildings and “three-dimensional” lanterns that look like they are hanging off buildings. Another bonus: Walking down Broadway in pajamas—or whatever ultra-casual wear you prefer, really—is more acceptable than wearing them in, say, the Crocker Art Museum. On Broadway, between 21st and Ninth streets; www.broadwayaugmented.net. J.M.