Heard a great one from John Hartford. Man's in an airport, carrying a banjo case, approaching the security barrier. The guard singles him out and beckons him over to the table.
   Says, "Excuse me, Sir, could you put that case on the table, please?"
   The man does so.
   The guard says, 'Now could you open up the case, please?"
   Sweating nervously, the man does so. Inside, for all to see, is a dismantled AK-47, a half pound of plastic explosives, and a map of the capital city with sensitive locations circled in red.
   The guard looks at for a minute, and says, "OK, you can close it up and proceed. You have a nice day, Sir. For a minute, I thought there was a banjo in there."