Richard Nixon gets Rowan & Martin on the Line (1973)

From the Video Description:

President Richard Nixon talks with Dan Rowan and Dick Martin from the popular television show, Laugh In. Nixon thanks the two men for a special skit they filmed for his private birthday party that had been held the previous day.

The skit was arranged by Nixon's friend Paul Keyes, who was a writer on Laugh In. It was Keyes who had gotten Nixon to make his famous appearance on Laugh In during the 1968 campaign, when he said the show's catchphrase, "Sock it to me?" The three men also discuss football, a particular enthusiasm of Nixon's.