Confirming a rumor that first appeared in March on the FDIC Fan Forum message board, former Federal Reserve chairman Alan Greenspan came out of retirement Tuesday to raise interest rates on federal funds by a quarter of a point. 'You may remember this one from 1989,' said Greenspan, barely audible above the roar of an estimated crowd of 20,000 gathered in front of the Marriner S. Eccles Building. 'But before I start, I think I'm gonna need [current Federal Reserve chairman] Ben [Bernanke]'s help with this. C'mon up here, Ben.' Greenspan refused to comment on buzz that he was planning a five-nation comeback tour to stabilize international housing markets. 