Over a lavish lunch of king salmon, veal with morrel sauce and chocolate, UN Secretary-General Ban Ki-moon on Tuesday reminded Barack Obama that they will soon both be jobless.
"Mr. President, we need to find something to do," Ban told the US president.
"I challenge you to a round of golf! But please don't challenge me to a game of basketball!" he quipped.
Ban hosted a lunch at the United Nations for leaders of all 193 UN member-states attending this week's General Assembly meeting.
The former South Korean foreign minister will step down in December after 10 years as the world's top diplomat. Obama ends his eight-year term in January.
Ban led heads of state and government in a toast, raising his glass to "peace, prosperity and human rights across the world".