(Roller Derby is a partial-contact team-based race done on roller skates around an ovular track. If you've heard of it at all, it's probably from movies or television in the 70s and early 80s where roller derby took on more of the characteristics of professional wrestling than a real sport. The modern incarnation of roller derby, while it still has physical contact, concentrates on the sport aspect of the game. The hitting which is permitted is very restricted in what's allowed, so that combined with all of the safety equipment keeps it from being really dangerous. Bruises are common enough, but more serious injuries are no more common than in other team-based sports.)
Roller Derby is, properly speaking, Beth's hobby, rather than mine. However, like so many things in a marriage, the line between "mine" and "yours" is easily blurred. Beth joined a roller derby team in the fall of 2007, and in January of 2007 she roped me (not unwillingly) into becoming a referee.
I never roller skated before, excepting a birthday party or two 15 years ago, so it's been really interesting learning how to get fast on roller skates. (I'm a pack referee, so we skate around the outside of the track, meaning that we have to be going faster than most of the player just to keep up with them.)
I haven't had a chance to be a referree since Beth and I moved to Pittsburgh, mostly because someone needs to watch the kids while the other is on roller skates, but I still follow Beth's exploits with interest.