http://www.treehugger.com/files/2009/05/ghent-goes-vegetarian.phpBasically, on Thursdays restaurants and schools and such will serve vegetarian food.
An interesting idea, for sure. It's an effort to reduce obesity and greenhouse emissions ("According to the United Nations' data, meat production and consumption are responsible for 18 % of global greenhouse gas emissions--more than cars. The Vegetarian Association says: 'if everyone in Flanders does not eat meat one day a week, we will save as much CO2 in a year as taking half a million cars off the road.' All civil servants and politicians are committed to no-meat Thursdays but everyone is invited to join the fun and abstinence."). I feel the need to point that out because people don't realize how bad for the environment the meat industry is
Anyways, it's obviously not a requirement for people, they can eat whatever they want, but the politicians are committed to it, and they invite people to do so as well.