I've been back in the LBJ Presidential Museum and Archives. The last time I was there I took some video of the animatronic LBJ reciting some of the president's favorite jokes. The whole exhibit goes on for somewhere between five and ten minutes, and uses excerpts from actual speeches or other public presentations. Only two of the jokes are in this video. It was a different time then; among other things, the President of the United States could tell jokes about being drunk.
My archival research is moving slowly. Here's a picture of a State Department memo pertaining to the Gulf of Tonkin Incident of August 1964. You're allowed to request photocopies of documents, but it takes over a week to get them. They let you bring digital cameras (or use one of theirs) to photograph documents to blow up and read later. It actually works pretty well.