Actually, that one wasn’t true. While there are many many examples of Sarah Palin running her mouth and saying idiotic things, the “she thought Africa was a country” meme was actually a hoax. Even the New York Times admitted it.
http://www.randomjottings.net/archives/003631.html
Still, this doesn’t change the fact that she is still either A) amazingly stupid, or B) willing to say things she knows are clearly un-true in order to score political points. Take your pick.