Friday the 13th is a date considered to be bad luck in western superstition.
According to folklorists, there is no written evidence for a "Friday the 13th" superstition before the 19th century.[1][2][3] The earliest known documented reference in English occurs in Henry Sutherland Edwards' 1869 biography of Gioachino Rossini:
(... from Wikipedia on 2012-04-17 16:50:43)