I was correct on my assumptions above, but obviously, there was so much more to it than that. I regret that I did not research the rules of the game before going. It wasn't as violent as I thought it was going to be (like on tv), but there was a lot of falling down involved. After a few jams (two minute races between teams to score points) I eventually began to somewhat understand the gist of this girls only sport. I chose my favourite team (Riot Girls) and "jammer" (the one who scores and has a star on her helmet) and spent the rest of the evening just enjoying the derby.
Aside from being confused about the rules, I found it to be quite entertaining. It actually reminds me a bit of men's hockey (bashing each other, blocking, racing). The league seemed like a good community of colourful people who were just out to have fun, with many volunteers helping out.
I think I will go again.
The next one will be on May 4th, at Minoru Arena in Richmond.