You can call it art.
You can even call it collaborative online-art, whatever. First do it, then name it - if you feel like. Possible online-creativities during a wiki-Woodstock are:
[[theatre?]]
[[dancing?]]
[[photogaphy?]]
Online-creativity creates results, pictures, music-recordings, videos etc. that we should collect and publish. All of this should be free and open btw. We will need a picture gallery and download-space for sound and video files.