PL/I
In short, PL/I is a crazy old programming language.Richard Holt's paper Teaching the Fatal Disease is a good read, it'll make you laugh :)
More PL/I information: http://home.nycap.rr.com/pflass/pli.htm
See COBOL, FORTRAN, ALGOL, MULTICS
This page is linked from: CLiki Bugs Multics PL 101 REXX The True Story of Ada