And then there's the classic Bush Bashing Rant which probably takes up a significant amount of class time.
Fortunately where we are (upstate SC) you don't see much of that in school. However my daughter gets plenty of revisionist crap at the local community college. But, the professors don't have to make a big effort with it, as the textbooks have been all "adjusted" to reflect the proper leftist and multicultural talking points.