Breweries
Wisconsin is home to many great breweries (and some not so great ones).
See also Brew Pubs
Nearby Breweries
Capitol Brewery in Middleton. The tour is nice, and in the summer they have a large, outdoor beer garden with live music most every weekend. And the beer is pretty decent too. If you plan to go frequently, buy the big plastic mug. Though expensive to start, the refills are cheap.
Tyrannena has some of the best beer anywhere! For $8 you get a sampler of 9 glasses of some of the best beer I have ever had. Also available on-tap some places around town, but the beer is better at the brewery. Live music most Saturdays. About 1/2 hour east of Madison in Lake Mills (take I-94 toward Milwaukee). They have tours in the summer months every few weeks. They are pretty informal, but fun.
New Glarus Brewing Company in New Glarus, home of the Spotted Cow and many other delicious microbrews. Free tours available every day, $3.50 for tasting three beers. New Glarus is southwest of Madison; to get there, take US Hwys 18/151 to Hwy 69 South.
Other Wisconsin Breweries
Leinenkugel's in Chippewa Falls. They have a nice Lienie's Lodge where they serve beer before and after the tour. And, unlike most breweries, you can get free beer even if you don't go on the tour.
City Brewery in La Cross. Never been to the brewery, but you can get La Cross Lager at Woodman's for about $12 a 30-pack. The been is light and mediocre, but its still the best beer for the price
Miller Brewery in Milwaukee. The tour is impressive. The beer is less so. But hey, it's a Wisconsin tradition. Or something.