It was Thursday in Chelsea when a gallery director told me about See Saw, an iPhone app that maps out openings in the simplest way possible. You view a finely built list of shows by neighborhood or opening date, press the plus sign next to the slot of a show you plan on seeing, and it appears on the map that has all your picks as red-hatted pins. I had never heard of the thing, but the director assured me everyone was using it, that it’s the hip, minimalist version of the bulky and expensive Artforum app, and that it was free. He was right. I used it all weekend.