I've never visited any of them but I've driven past a few.

I have heard from college kids that if you take a tour of the breweries in Monroe and New Glarus, they give out numerous free samples throughout the tour and they don't check ID's either.
Speaking of college, there was an article in the paper last week stating that the UW-Platteville microbrewery will be shutting down after six years on campus. A part time brew master at UW-Platteville said that as far as he knows, the campus microbrewery is the only university microbrewery that sells the beer it makes. Other universities that have breweries only use them for teaching purposes and the beer is disposed of after brewing. Evidently the UW-Platteville microbrewery was losing money and it will no longer be feasible to keep it operating.
A brewery on a college campus losing money? What's up with that?
Actually, my son said the college "drinking crowd" prefers to go to the down town bars and since they are in walking distance from the campus they don't have to worry about driving drunk.