For my family in Wisconsin, nothing beats a week in Boulder Junction, Wisconsin. My parents went up there every summer for years, and I have a nephew who has a cabin up there. The name always tickled me. It pretty much explains what there is to do up there for excitement. "Hey, Maude, want to go out and look at the boulders this weekend? :-)
If you really get bored, you can drive west and spend the day exploring the wonders of Moose Junction in Wisconsin, over near the Missiossippi.`
If you like trees, you might drive east and go to Arbor Vitae, Wisconsin.
Or drive north to Cornucopia, where life is overflowing.