Saturday the 15th of December was the only day I could join the protests in Brussels (my 7-year old daughter had the flu, so I missed Thursday and Friday).
There were two meetings and marches: one was organized by a group called D14, which had distributed most of the information leading up to the protests. The other was advertised as an "anarchist" gathering. A friend and I decided to go to the D14 meeting because they seemed to be the "official" organizers of the protests, and also because we were a bit unsure if the term "anarchist" meant the "black-hooded," violence-provoking "anarchists" at other anti-globalization protests. 
The D14 meeting was supposed to begin at 10AM in the auditorium of the University. There are two universities in Brussels, with adjoining campuses: one French speaking, the other Dutch speaking. It turned into a typically Belgian situation: there were no signs explaining where to go, and all the people we asked were also looking for the meeting place.  We finally learned that the meeting was at an auditorium at another campus 2 kilometers from the main campus. 
By the time we got there, things were winding up, so we thought that we’d stick around and join the march. I should mention that D14 is connected with Indy Media Belgium, another reason why we had decided to join them. As we walked around we saw that pretty much all the information, banners, etc. were communist, and the only political party present was the PVDA, which is the Belgian communist party. Now, I’m not "anti" communist, but I wasn’t exactly enthusiastic about marching behind posters of Karl Marx and Che Guevera. I may admire both, but I’m no groupie of theirs, nor did I want to be associated with loyal communist party types.
After checking out the communist scene we decided to see what the anarchists were up to. When asked to describe my political/social philosophy, I usually describe myself as an "anarchist," although I’m really more of a fellow-traveller, and more willing to make compromises (like working with the New York Greens) than a "real" anarchist.
Naturally, the anarchist meeting was on the opposite side of Brussels from the communist meeting, and the tram connecting the two sides of town wasn’t running because of the protests (other trams seemed to be running though…). The anarchist meeting was scheduled for 2PM, and since we stopped at a friend’s house on the way, it was 3PM by the time we got there.  En route we ran into some funky-looking people who asked us which way to the anarchist meeting, so we walked together. They were students from the university and, like us, were turned off by the doctrinaire communist attitude of D14 (a woman from Portugal told me that she had been there the day before, and that the communists wouldn’t dance to the music like the anarchists). One of them was working on a video about the protests, and video taped us as we talked about the violence issue. I told them that I’m working on a video about 9/11 – about the "evidence", non-response on the day of the attack, the conflicts of interest with the pipeline, Osama’s resume with the CIA, etc. – and we all traded contact info.
We caught up with the anarchists at the gare du midi, and it was great: a real street party. The theme was to claim a "free space" in Brussels. There were only about 2000 people, but as we marched through the city our numbers grew – although in the narrow streets there was no way for me to determine by how many. All of a sudden the "black block" anarchists showed up, but all they did was spray paint graffiti. This was not at all cool though, because we were in a working class neighbourhood – mostly Moroccan – and this was not the way to appeal to them. It was the one fucked up thing I witnessed. 
After some time the police showed up – a helicopter had been following us the whole time – and in force. There were maybe 3000 of them in full riot gear, with military vehicles and water canons. They sealed off all the streets around us and for a while it looked like they were preparing to attack. After an hour they let us continue, although from then on they hemmed us in as we marched. As I understood we were supposed to meet up with D14 and form a bigger group, but the police didn’t let that happen. We were forced to return to the gare du midi, at which point the momentum was lost and the march ended.
Later, while waiting on the train platform, we saw some other people who had been at the protest, and learned that while we had been drinking coffee at our friend’s place there had been some real violence, in the form of the black-hooded folks smashing bank windows, vandalizing every Mercedes Benz they could get their hands on, and throwing molotov cocktails. Apparently they were trying to get to Laken, which is the neighborhood where the EU talks were taking place. 11 were arrested. Not that bad, really…