I went to Wisconsin a couple weeks ago and had some fun hanging out in Madison with my Aunt and her family. Part of the trip was dedicated to beer and cheese. New Glarus is about 25 miles from Madison and the brewery is still in a fairly small building along the highway (its moving soon). The tour is self-guided, with this radio/phone thing that you use. The sign over the hops says "17", so you type "17" on the phone and listen to someone explain hops, etc etc.
NG has some cool copper brew kettles that are probably worth a fortune.
Overall, however, I was disappointed with the experience. Why?
For one, the lady working the combination gift shop/tasting area seemed very disinterested in helping us. She also didn't know a damn thing about the beer. Tasting was $4, which included a tasting glass (reasonable), but during the week, the tastings are from semi-chilled bottles which sit in a mini-fridge under the sink, not from kegs. There is no choice of what you taste, you get whatever 3 beers that they decide to offer for tasting that day. (She also served them in the wrong order, but I can cope with that).
Then there's the beer. So the general buzz about NG is that they are the second coming and they offer the best beer in the world. Sorry guys, but that ain't true. NG's beer is okay, but they are too focused on lighter, low flavor, lagery type beers. (At least those were the 3 I tried that morning).
Anyway, NG is worth a visit, but don't expect it to top anything from Fort Collins, Boulder, or Denver. (okay, yeah, I'm a bit spoiled).