Soccer, softball, skiing, jogging slowly, and most recently cycling.
Everyone in the derby community.
Being brave. Good posture. Blowing a whistle.
I had no idea what roller derby was at my first SDDD bout, but 2 days later I found myself signing up for bootcamp and the Stripes program. Now I have a much better idea of what roller derby is, have met all sorts of cool people, and can roller skate better than I had ever imagined possible for myself.