It started with Gerry Adams forcing Sammy Wilson's arm into a Mexican wave, writes Claire Cromie.
In a rousing speech at Belfast's Waterfront Hall on Monday morning, US president Barack Obama urged the young people of Northern Ireland to build on the successes of the peace process and strive to heal the divides that still afflict the region.
Addressing an audience of 2,000 invited guests, the majority of whom were school children, the president said it was up to young people to challenge hardened attitudes and prejudices and push the current generation of political leaders to drive towards lasting reconciliation.
America's First Lady Michelle Obama also spoke at the Waterfont, before travelling to Dublin with their daughters.
Obama then made the journey to Fermanagh where he and David Cameron took a break during intense discussions about Syria and other issues facing the G8 summit to help pupils with a mural at a local school.
The two leaders visited Enniskillen Integrated Primary School as they prepared for the formal start of the two-day summit being held in the Northern Irish town.
En route in the president's armoured car, known as The Beast, the pair discussed the fraught issues facing global leaders gathered in the UK for the annual talks, most notably the serious split in the international community over the Syria crisis.
Monday afternoon saw Europe and America launch talks on a free trade deal which Prime Minister David Cameron believes could add £100 billion to the world economy.
Cameron also had talks with Japanese Prime Minister Shinzo Abe, whom he last met as leader of the opposition in 2007, and said he hoped to further develop "the very good state of bilateral relations between Britain and Japan".
But the day ended with the Western nations facing down Russian president Vladimir Putin over his support for the regime of Bashar Assad in Syria.
Divisions between Moscow and the West were laid bare at the annual gathering of world leaders, which comes days after President Barack Obama suggested the US may send weapons to the Syrian opposition.