Leon Lederman:  Almost all of them seem to happen at three o’clock in the morning, mostly on Thursdays.  I don’t know.  There is that occasion when you realize that you’re learning something that nobody else knows.  It may be you’re alone.  It may be you’re with a graduate student.  It may be you’re with a colleague.  Sometimes it’s very gradual.  The data accumulates slowly, and there’s not what we would call the “eureka” instant.  But sometimes it does happen that way.  I can remember several examples of suddenly realizing that the world is very different from the way the four billion people or so that are on the planet know about it.