Roller derby is a full-contact team sport on skates. The game takes place on an oval track, each team fields 5 skaters: 4 blockers and one jammer with a star on the helmet. Jammers gain one point for every opponent they lap. Blockers perform defensive and offensive duties: they prevent the opposite jammer from passing and help their own jammer pass the opponents. The game is played in a series of short (up to 2 minutes) shifts, called jams. Each team has a roster of 14 players and typically fields different skaters for each jam. There is a comprehensive set of rules ensuring safety and fairness of the game, which is enforced by 7 referees. Any skater violating the rules is sent to the penalty box for 30 seconds. Here is my presentation on basics of Roller Derby [pdf, keynote]
From March 2015 till August 2016 I was a unicorn, a skater with Capital City Roller Derby (CCRD). Very briefly I was a skater of a co-ed team Fear & Loathian (F'n'L). I've been a skater with Les Moustaches (defunct since mid-2017) and currently I'm a skater with RATM and Team Poland.
From March 2016 till August 2016 I was a baby zebra, an apprentice referee with Auld Reekie Roller Girls (ARRG). I have been a ref with Roller Derby Lille (Auf Wieder Zèbres) but as of recently I've been refing only occasionally.
My officiating stats can be found here [https://goo.gl/NkAJUH].