In the fall weve got the scenery with the leave turning colors (ya missed it by about a week) In the winter weve got the snow which is a BLAST to drive in and go snowwheelin! and in the summer weve got the Dells water parks.
If ya come snowwheelin or snowmobiling make sure your prepared (heavy clothes, extra clothes, tow straps, tire chains, food, water, heater, AND A BUDDY)
I'll give you one big general reason that you can research further:
Lot's to do in the great outdoors all year! But we also have the finer things in life too.
My list includes:
canoeing, hiking, biking, fishing, driving, Wisconsin Dells (go karts, water park, etc) AND indoor waterparks when the weather is too bad to be outdoors. There is also Frank Lloyd Wright, Lambeau Field, Door County, Lake Geneva, Miller Park, Museums, Madison, etc, etc, etc. Whether it is taking in a sports game, the theatre, a museum, a night out a a great restaurant, there is a LOT to do in the state of Wisconsin.
Oh and like others posted, Beer, Brats, and Cheese. There is also a mustard museum!
Where to start. Try Wisconsin Dells, Green Bay (Lambeau Field), Miller Park, Summerfest, Northern Wisconsin for fishing, hunting, hiking, horseback riding, Brewery tours at Lakefront Brewery, Leinenkugel's, Sprecher, New Glarus and all the other smaller breweries.