This is a three-movement divertimento in the key of F for strings and two horns written by Wolfgang Amadeus Mozart. It was written in the year that his father died, as was another divertimento, the beautiful and well-known Eine Kleine Nachtmusik. Mozart added this piece to his catalog in 1787, but the first of the three parts was written about three years before the second two.
A musical joke
The music contains deliberate compositional mistakes, incongruities, wrong notes, disharmonies, misuse of instruments, stretches of simply uninspired tune and an absence of interesting ideas. The title translates to "A Musical Joke." Like others over the centuries, we have to wonder on whom was Mozart was playing this joke. The wily Mozart, it seems, never told anyone, so naturally a number of contentious theories have been proposed.
A joke on who?
The first movement is reportedly based on a work composed by village musicians, so the obvious and most pedestrian theory is that Mozart was making fun of the simple, minimally talented rural folk. Well, perhaps Mozart was so unkind a man as to actually do that, but would he waste his composing time on such a trivial and mean goal?
Another theory is that he was trying to parody particular contemporaries, or perhaps all of those poor non-genius composers in general. Evidence against this view is that many of the mistakes are so elementary and blatant that very few of the even mediocre composers of the day would actually make them. Still further evidence that this was not just a mean joke on the country oom-pah-pah of the day is that the second part differs in sophistication from the first part, which was written earlier and reportedly based on village musicianship.
Of course we can expect more complex thinking to be applied to this great question. One theory proposes a "feigned lack of imagination." in which the surface clumsiness, obvious 'mistakes' and lack of apparent inspiration hide a deeper layer of artistry. An example of this overwrought thinking is that the apparent discordance at the end of the piece masks actual triads formed in E-flat major, because the instruments that play the chords are themselves tuned in different keys.
Another idea about hidden complexity beneath apparent mediocrity was suggested by Luis Baptista, a prominent ornithologist. Mozart had a dear pet starling, a bird that can sing two intertwining melodies simultaneously with its two vocal cords, sometimes a bit off-key. Baptista felt that Mozart was imitating starling song in Musikalischer Spass.
The consensus seems to be that the joke was for the entertainment of the audience. No one, it seems, wants to suggest that the audience may be the butt of the joke. Maybe this was Mozart's revenge on unappreciative audiences. He tells them this is a joke, but they lack the musical sophistication to see exactly where the joke is. In any case, he certainly provides a savvy listener plenty of opportunity to impress his or her date by helping them 'get it.'
Joke or just a little fun?
There is also a view that "Joke" may be a misleading translation of the German "spass", which perhaps more often means simply "fun" rather than "joke on someone". Maybe the genius was just being playful and trying to ground a field of endeavor that tends to take itself too seriously by setting a perspective.
Listen to it yerself.
Did you laugh? Do you wish you knew where to laugh? Is it about laughing at all?]
Pet bird theory
As most believe