There´s a festival for urban projections since 2006. Stops so far were Florence (Italy), Milano (Italy) and Dublin (Ireland) this february.
This is what they say:
“The International Guerrilla Video Festival (IGVFest) is a mobile festival integrating video art with the urban and social environment. The festival removes the technologically complex medium of video out of the institutional situation re-positioning it as open and reflexive in the public domain. The artworks have site-specific thematic relations to the space where they are shown, engaging and reflecting upon the unique architectural, historical, and interpersonal context of each area the festival travels to.” read more on their website.