The Vermont Brewery Passport is something they've been doing for a while. I got a card when I was up there for my honeymoon. Unfortunately, we had already visited 4 of the 18 before the 5th one (Rock Art) gave us the passport and stamped it for me.

bryan said:

I've heard of this festival from many people at other beer fests, so I'm anxious to check it out.

If you're going to be up in the area before the event, they're also hosting a "Brewery Challenge". Pick up a "passport" at any of the breweries up their, then get it stamped at every brewery you visit. There are prizes at the 4, 10, and 18 stamp levels.