For years, Wikiquote has been smearing Rush Limbaugh by falsely pretending that he said the following (en.wikiquote.org/w/index.php?title=Rush_Limbaugh):
You know who deserves a posthumous Medal of Honor? James Earl Ray [the confessed assassin of Martin Luther King]. We miss you, James. Godspeed.
The article "Wikipedia's zealots" from Lawrence Solomon of the Financial Post (link) details issues with the WP article about University of California San Diego professor Naomi Oreskes, who wrote a paper claiming that there was wide consensus about global warming. The paper was challenged by UK scientist Benny Peiser: