Yesterday the Improv Everywhere gang took 2,000 dogs for a walk in the Cobble Hill area of Brooklyn. Invisible dogs, that is. You remember those old invisible dog toys, right? Turns out the circa-1970s toy was manufactured in a Brooklyn factory, which now contains the Invisible Dog art space! The space loaned the pranksters the vintage dog leashes for their afternoon of good clean fun; and if you want one yourself they still seem to be for sale online. More photos from Katie Sokoler, here.