Between January and September of 2010, Jay Leno made more jokes about Al Gore than about Sarah Palin. You read that right. This is while Palin was promoting books, making TV specials, stumping for candidates, and basically in the news every day, while Gore was doing what exactly? Once Al Gore became the unofficial spokesperson for concern about climate change, it was increasingly inevitable that Republicans would deny it on principle.
(Photo of the "world’s first graffiti on polar icebergs" via Buzzhunt)