Stroom Den Haag is a Netherlands based design, visual arts and architecture activity center. This is the best way I can seem to describe what they actually do. What I know for sure is that they do a lot of really amazing art and architectural projects for their community.
Above are pictures from an intervention done for the De Paradijsvogel elementary school. The project was completed by Marleen Kaptein and Stijn Roodnat (also known as KapteinRoodnat). The intervention consisted of hundreds of meters of bright green tubes that occupied not only the schoolyard, but the assembly hall as well.
Be sure to check out all of the amazing projects Stroom has at their website, definitely not something to miss!