During this era, NBC experimented with broadcasting emerging sports. In 2001, the network partnered with the World Wrestling Federation (WWF) to establish the XFL – a new football league which introduced modified rules and debuted to tremendous, but short-lived fanfare, only lasting one season (NBC shared broadcast rights to the league's games, which were mainly held on Saturday nights, with UPN). In 2003, NBC obtained the broadcast rights and a minority interest in the Arena Football League. The network televised weekly games on a regional basis, as well as the entire playoffs. The deal lasted four years, after which the league and NBC parted ways.