The Principality of Sealand
He seized the offshore platform in 1967 and has defended it along with others ever since. (Using grenades and petrol bombs to good effect)
But did you know they actually had a national football team? Here is the story of the Sealand National Football Team
Founded in 2003, the first Sealand National Football Team consisted of retired players from the Danish veteran side named Vestbjerg Vintage Idrætsforening, from Aalborg. They played their first game on May 15th, 2003, in an entertaining draw away to Aaland, another small island nation, just off the coast of Finland. The game ended 2-2.
However, the Sealand National Football Team did not play another game for nearly 8 years, when they played their second game against Chagos Islands, an archipelago from the Indian Ocean. This game was played at home, but they lost to the visitors, 3-1, on May 5th, 2012. Actor Ralf Little played for the Sealand National Team that day.
They didn't have to wait long to play again because in August of 2012, they played one of the Channel Islands, Alderney. The game ended 1-1. However, Sealand won, 5-4 on penalties.
2013 proved to be a busy year, with SNF playing four games in the calendar year. First, take on Alderney once again on March 8th, beating them 2-1 at home.
Their second match took place against a side based near Sri Lanka, Tamil Eelam national football team. They lost at home to them, 5-3, on July 4th, 2013.
An 8-0 defeat followed to the Occitania national football team the very next day on July 5th, 2013. However, two days later, they beat Alderney, 2-1.
2014 saw them play even more matches, six in total, against the Chagos Islands, Somaliland, Raetia, Seborga, and then finally a 4-1 loss to Panjab.
It was after this that the nations football team became defunct and have not played a single match since.
The Principality of Sealand has only one known resident on it at present, so I doubt they will be returning to the footballing world anytime soon.