This was my second time at Roller Derby, the last time was in 2013. However, this was the first time that I had the rules explained to me, which really helped me to understand the game. This was between London ‘A’ and Dublin ‘A’. I was part of an outing with Offshoot Photographic Society. Roller Derby involves two teams of five players in play at any one time. I don’t know how many players are on the entire team. One player has a star on their head and they are called the Jammer, they get a point for every player they pass. If they get stuck they can pass the star to the player with a stripe, and that player becomes the Jammer. The other four players are meant to prevent the Jammer from getting around the track. Each section lasts two minutes, then the players swap out and the game starts again, each game lasts one hour. It was an interesting game to watch. I have included the website addresses for both Offshoot and Dublin Roller Derby below.
http://www.Offshoot.ie
http://www.dublinrollerderby.com
Gallagher Photography 
I have a friend who takes part in Oxford, looks terrifying!
Thanks for your comment Jane, yes, it looks a bit mental, and chaotic. However, when you watch it for a bit, it starts to make sense. I have a cousin who plays it in Canada, and she looks like she has an amazing time.
I really like your blog, just followed!