"Art" is so loosely defined that some people are really taking advantage of pushing the limits of its definition. There's definitely a point where we can safely say "Come on... that is definitely NOT art!" But sometimes what crosses that line is totally ambiguous and hotly debated.
Anyone who's stumbled into an art gallery or two (especially in Europe) knows how popular the image of the Madonna is as an artistic subject. Chris Ofili's 'Holy Virgin Mary,' however, takes a fairly interesting and novel approach to representing the virgin mother, incorporating pornographic clippings smeared with elephant dung. The artwork was housed at the Brooklyn Museum of Art in New York, and the gallery saw its funding temporarily withdrawn following outrage from the Catholic Church, Mayor Giuliani, and elephants. The gallery sought an injunction and the court sided with them by reinstating their funding and curbing any attempts by the city to remove the piece.