Thanks to Travelzoo for the heads up:
Delta is offering a $358 round trip fare from New York to Manchester, England (England, across the Atlantic Sea, as they sang in HAIR) good for departures through July. You can return through the end of August. This is about half what is costs to fly anywhere else in Europe. Cheap flights are available from Manchester to nearly anywhere else in the UK or Europe, so it’s a great launching point.