Anchor Brewery in San Fran. Unlimited free tastings of most of their brews at the end of the tour. You end up socializing with other people that took the tour. I think I stayed an hour and was healthily buzzed. Totally free too.
in '87 i remember the Mauna Loa Macadamia Nut Factory on the Big Island of Hawaii. the macadamia nut brittle was fantastic.