The best non-Hitchcock example of a MacGuffin is The Maltese Falcon in the novel and movie of the same name: the fact that the statue is a falcon—or even that it is a statue—is entirely irrelevant, and all that matters is that there is a prized object over which many characters are fighting.
The 1930s were a fertile period for Hitchcock and saw the release of his best-known and best-remembered movie from his pre-Hollywood time: The 39 Steps, based on the John Buchan novel was the movie that introduced the film concept most associated with Hitchcock. The “MacGuffin,” a plot device that drives the story but is essentially unimportant to it in its specifics. The best non-Hitchcock example of a MacGuffin is The Maltese Falcon in the novel and movie of the same name: the fact that the statue is a falcon—or even that it is a statue—is entirely irrelevant, and all that matters is that there is a prized object over which many characters are fighting. A more recent and sly example is the briefcase in Pulp Fiction, the contents of which are never even revealed. A MacGuffin provides motivation, but all that matters is that the characters want to obtain it, which automatically builds conflict as multiple characters cannot all have it.