I have never been to an actual Roller Derby meet/match/game/event but I used to love to watch it on TV when I was growing up.  Back in the day there were men's and women's teams and they skated on banked tracks at what looked like very high speeds.  The jammers for both species were pretty big and bulky, if I remember correctly!  I don't remeber any music being played, but at that point it would have been Perry Como or Frank Sinatra, not exactly speed skating music.  There was only a lot of loud yelling and screaming!