A cool video from FilmmakerIQ, where Alfred Hitchcock explains the concept of a “McGuffin”:
For those of you who don’t have 1:44 to watch the video, here is some of what Wikipedia has to say on the subject:
The director and producer Alfred Hitchcock popularized both the term “MacGuffin” and the technique, with his 1935 film The 39 Steps an early example of the concept. Hitchcock explained the term “McGuffin” in a 1939 lecture at Columbia University: “[We] have a name in the studio, and we call it the ‘MacGuffin’. It is the mechanical element that usually crops up in any story. In crook stories it is almost always the necklace and in spy stories it is most always the papers”.
- It might be a Scottish name, taken from a story about two men in a train. One man says “What’s that package up there in the baggage rack?”, and the other answers “Oh that’s a McGuffin”. The first one asks “What’s a McGuffin?”. “Well”, the other man says, “It’s an apparatus for trapping lions in the Scottish Highlands“. The first man says “But there are no lions in the Scottish Highlands”, and the other one answers “Well, then that’s no McGuffin!”. So you see, a McGuffin is nothing at all.
Hitchcock related this anecdote in a television interview for Richard Schickel‘s documentary The Men Who Made the Movies. Hitchcock’s verbal delivery made it clear that the second man has thought up the MacGuffin explanation as a roundabout method of telling the first man to mind his own business. According to author Ken Mogg, screenwriter Angus MacPhail, a friend of Hitchcock’s, may have originally coined the term.
Some examples of McGuffins in movies:
- The meaning of rosebud in Citizen Kane (1941).
- The top secret plans in The 39 Steps (1935).
- The eponymous statuette in The Maltese Falcon (1941).
- The letters of transit in Casablanca (1942).
- The uranium in Notorious (1946).
- The case with glowing contents in Kiss Me Deadly (1955).
- The “government secrets” in North by Northwest (1959).
- The mineral unobtainium in the 2009 film Avatar. 
- Uri’s lucky painting in RocknRolla.
What other McGuffins can you recall?