We did plain old Slug Bug until my mother complained that we were beating each other too much.

I always liked cow bingo (or horse bingo, or dog bingo). You make a list of cows or horses or whatever animals (colors, breeds, whatever) and the first person to see all of them wins. It works better in some places than others, though. (No good in dairy-farming Iowa, "Holstein. 'Nother Holstein. Damn, there's a lot of Holsteins around here. Oh, wait, black Angus! . . . Holstein.")