Mitchel, I've got towns that I shoot in that are anywhere from half a quarter, all the way to a full section and anything in between. Of course, a section is 640 acres, and a quarter is 160 acres. Some towns out here are spread out over more than one section, so there's some pretty big towns.
I'd say on average, that the majority of the towns are in the "quarter size" category though. That's why I'm splitting everyone up into teams, so I can get everyone into a town, and have plenty of shooting.