...What is roller derby?
Roller derby is a contact sport where players are women, played by two teams of five members roller skating in the same direction around a track.
it is an old sport and it started in the 1920es in America. Now Derby is back and there are already several teams in all continents!
for more info visit:
http://en.wikipedia.org/wiki/Roller_derby
http://de.wikipedia.org/wiki/Roller_Derby
http://it.wikipedia.org/wiki/Roller_derby