I saw a report on the BBC a couple of days ago about the sporting phenomenon of female "roller derby", which is apparently migrating from the US to the UK. Essentially, ladies roller skate around a track in a team and try to knock their opponents to the ground. Pretty much anything goes and broken wrists and ankles are accepted as a recreational hazard.
The correspondent implied that it was the new way for ordinary moms in America to let off steam, although the preponderance of outlandish tattoos and piercings suggested that the participants would perhaps be more at home on the set of Jerry Springer than they would at a Tupperware party.
It definitely has a girlpower attitude all of its own. As demonstrated by Sweet Sherry Pie, a Joysey dame who hangs with the Gotham Girls: http://www.gothamgirlsrollerderby.com/month/