underground sport

An underground sport is one that is too risky for the general public. Players establish a sense of community with each other through dangerous acts and it is considered separate from the community of their city or town. So basically, only badasses can play them.

Skateboarding is an underground sport because players share a sense of thrill and danger with each other.

Street hockey is an underground sport.

Hacky-Sack is not an underground sport.