Matt Siber ‘s Floating Logos project eliminates the poles that allow signs to be viewed from a long distance away.

The poles are digitally removed from the image in order to create a floating effect meant to call attention to the hegemonic role consumerism and advertising play in our society.

Via J-Walk blog.
See also Swanksigns for street signs which are just begging to be mocked.

And Panos who makes and installs fake road signs in the Lyon (France) area.