From today's New York Times (third item):
"A French appeals court yesterday upheld the three-month suspended sentence given to a 78-year-old Frenchman who attacked 'Fountain,' Marcel Duchamp’s porcelain urinal, with a hammer last year .... Pierre Pinoncelli chipped the urinal, valued at $3.6 million, in January 2006 at an exhibition of the Dada movement at the Pompidou Center in Paris, and scrawled 'Dada' on the work."
According to the Times, Pinoncelli also urinated on "Fountain" at a 1993 exhibition and once "cut off a finger to express solidarity with a French-Colombian politician being held hostage in Colombia."