Art House Co-Op is a great organization based in Brooklyn N.Y. that hosts worldwide art installations that are open to the public-anyone can participate! Some projects are free and others charge a small fee to cover supplies and the work it takes to organize the projects. I have participated in the Sketchbook Project and many of their free projects. Here are a few of the pieces I have sent in:
The first painting is watercolor , the second is colored pencil, and the third is pen and watercolor.