About Street League Skateboarding. Street League Skateboarding (SLS) is the first-ever professional league for street skateboarding. SLS features 25 of the world’s most exciting skateboarders competing in an easy-to-follow, ISXTM instant scoring format on one-of-a-kind concrete skate plazas, all for the largest prize purse in skateboarding history. Each arena stop of the 2015 SLS season will air live on FOX Sports 1 and FOX Sports GO with a live international webcast on Streetleague.