One of major goals of our trip to Belgium (the other being to watch AFC Tubize play) was to sample the beer at the Westvleteren Brewery. It's a Trappist abbey, so it's real monk-brewed beer. The brewery is part of the claustrum and thus is not open to visitors. But there's a visitors' center across the street where they sell their beer.
Aside from getting the beer there, they will only sell one case per phone number per month, and you have to pick it up in person. So it's not exactly easy to get a hold of. I don't think we saw it at any of the bars in Belgium; it wouldn't be practical to keep it in stock, I imagine.
We had originally planned to bike all the way from Bruges to Westvleteren, but we weren't able to rent bikes for long enough to make the 35-mile trip (both ways) possible. So we had a very nice train ride from Bruges to Kortrijk to Poperinge, and then an even nicer walk through the countryside, about three miles, from Poperinge to Westvleteren. Follow along on the route we walked!
The best part of this trip: carrying a six-pack all the way back into town. As we came into Poperinge, people recognized the beer we were carrying, and they were clearly amused that we had walked all the way there. They would smile at us from their immaculate lawns and say things that we couldn't understand, and we'd smile back and make some gesture that indicated we concurred.