Chris Chandler and the Passer Rating System
Chris Chandler had a long (16 seasons) NFL career as both a starting and backup quarterback. He played for the Colts, Buccaneers, Cardinals, Rams, Oilers, Falcons, Bears, and then the Rams again. He played collegiately for the University of Washington Huskies.
There are many mysteries surrounding the Passer Rating System used to assess NFL quarterbacks, but a score of zero is of course the worst rating you can get while a score of 158.3 is the best rating you can get.
Chris Chandler has the distinction of being the only quarterback (through the 2006 season) to have achieved both a zero rating in a game and a perfect 158.3 rating in a game during his career.