Brussels was one of my favorite places on my recent European trip. We happened to be there on the eve of the Nuit Blanche, an all-night long festival of art, performance, music, and theater staged all over the city. After eating dinner, we wandered into the main square and were stunned to see this sight — green laser beams shooting across the square, just over our heads. They were pumping smoke (dry ice?) into the square, which the laser beams lit up. It was like a ceiling of green smoke over your head. Very cool. Click on the picture to see more images.
We wandered around for a while and saw some music, and some bad performance art. Coincidentally, when I was in Paris a week later it was their turn for Nuit Blanche! Unfortunately I was leaving on the Eurostar for London that night. But I got to see an art installation getting set up in the courtyard of the city museum in the Marais.