Bad signs can send perfectly ordinary citizens into spirals of obsession. Take Richard Ankrom, a Los Angeles artist who thought the junction of the 110 freeway and the 5 freeway was badly marked. In 2001, he put on an outfit that looked like the ones Caltrans highway workers wore, climbed up onto a freeway gantry, and mounted an aluminum sign he'd manufactured himself according to state specs. The sign stayed up for nine months without anyone noticing what he'd done; when the story leaked to the press and Caltrans finally cottoned on, the agency left the sign up for eight more years (eventually replacing it with one of their own that served the same function).

via Signs: The most useful thing you pay no attention to. – By Julia Turner – Slate Magazine. (Thanks Joel!)