Also on the LOC's list was William Jennings Bryan's Cross of Gold Speech. We actually discussed this speech on the blog when we asked "Which was the most important campaign speech?" This speech came in fourth. (You can see transcripts of all four speeches from that discussion here.]
I found an audio version of the speech (recorded by Bryan in 1923) on YouTube for you. It has an introduction from NPR. The person who put this up on YouTube has a question at the beginning - see if you can catch the narrator's mistake!