PRESIDENT HAS HIS LITTLE JOKE. WASHINGTON, D.C. JANUARY 14. PRESIDENT ROOSEVELT IS A GREAT RIBBER AND HARDLY A DAY PASSES THAT HE DOES NOT INJECT A LITTLE HUMOR INTO HIS SERIOUS JOB OF BEING THE NATION'S CHIEF EXECUTIVE. TODAY'S JOKE WAS AT THE EXPENSE OF ADMIRAL CARY T. GRAYSON, CHAIRMAN OF THE INAUGURAL COMMITTEE. FINDING AN ENGRAVED INVITATION TO ATTEND THE INAUGURAL CEREMONIES ON HIS DESK THIS MORNING, PRESIDENT ROOSEVELT WROTE THE FOLLOWING MEMORANDUM TO W.E. ROCKW... CHIEF OF THE WHITE HOUSE SOCIAL BUREAU: 'PLEASE REGRET THIS INVITATION. I WILL BE TOO BUSY' WHEN THE LETTER OF REGRET WAS SENT TO HIS DESK FOR FINAL O.K., PRESIDENT ROOSEVELT, PONDERED A MOMENT AND ADDED THE FOLLOWING NOTATION ON THE LETTER SHOWN IN THE PHOTOGRAPH. THE LETTER WAS THEN DISPATCHED TO ADMIRAL GRAYSON