Though summer music festivals almost never coincide with pleasant weather, it couldn't have been a lovelier day at the South Street Seaport Saturday for the Village Voice's 4Knots Festival. We showed up just in time to catch Eleanor Friedberger, who performed her atmospheric tunes in striped trousers amid a nice river breeze. If, however, you did feel overheated duringthe day-long concert, concert-goers could cool down in an air-conditioned indoor lounge on nearby Front Street where bands including Brahms, Yeasayer and Dan Deacon DJd until midnight. The crowd was huge and happy, full of twenty-somethings in sparse clothing grooving to the likes of Oberhofer and The Black Angels, who closed down the live portion of the evening. We had an excellent view of revelers and the stage from a hulking nearby sail ship, the Peking, where we enjoyed the music sitting in the sun and drinking beer -- we can't think of a better day to enjoy a summer afternoon.