"The Man Who Knew Too Much" falls into that Hitchcock middle ground that characterized many of his films during the 1950s: not a masterpiece of suspense by any means, but an awful lot of fun nonetheless.
James Stewart and Doris Day play a vacationing couple who get caught up in a plot heavy on foreign intrigue. The famous climactic scene takes place at a classical music concert, where someone is going to be assassinated during a particular cymbal clash in the score. The impish Hitchcock of course lets us know what that point is, so that the race to stop the assassin becomes a nail biting race against the cymbalist.
So much of this movie reminded me of the 1978 Chevy Chase/Goldie Hawn comedy "Foul Play" that I have to believe that film was inspired by this. Neither film is a big deal, but both are easy to enjoy.
Grade: B+