I think it takes place every Saturday morning to afternoon, vintage shopping while having a great view at the Manhattan skyline from the East River State park. You will find lots of vintage shops and warehouses around this area of Williamsburg.
The Future Perfect is my favorite place to shop for furniture / interiors, or pick up a small gift for a friend. They have a perfect mix of beautiful and strange objects, some of my favorites include the Animal Butt Magnets, Shrigley Salt & Petter Shakers, and the Bank in the form of a Pig.
I love enjoying some Amazing Vietnamese food at this place before heading out to the different bars around Jefferson on L. The restaurant is just behind Elsewhere so you have a nice mix of things to do if you start your night here.