Today there was an article in the New York Times about some guy who looked through the transcripts of oral arguments at the United States Supreme Court to find out what the Justices laugh about.
My favorite quote:
"Sometimes the laughter that apparently filled the courtroom is hard to comprehend. Chief Justice Roberts, for instance, got a laugh for this observation: "The relationship between the states and the federal government has changed a little since Gibbons v. Ogden."