Short answers, pulled from the story.
Haydn's Op. 33 String Quartets are a set of six chamber works written in the summer and autumn of 1781. They are called the "Russian" quartets because Haydn dedicated them to Grand Duke Paul of Russia, and many were premiered on Christmas Day, 1781, at the Viennese apartment of the Grand Duchess Maria Feodorovna.
The joke in Op. 33 No. 2 ("The Joke") occurs at the end of the fourth movement. A grand pause tricks the audience into thinking the piece has ended; a sudden forte note then shocks them, and the first violin restates the opening theme with progressively longer rests between phrases, creating repeated false endings before the music stops abruptly on a soft, incomplete phrase.
Op. 33 No. 3 in C major is nicknamed "The Bird" because the first movement opens with a first-violin melody built from repeated notes with grace notes inserted between them, producing what listeners described as a birdlike quality.
Some scholars believe the Op. 33 quartets inspired Mozart's own set of six string quartets, which Mozart dedicated to Haydn. No direct evidence has been found to confirm this, but the Op. 33 works were circulating in Viennese musical life at the time Mozart wrote his quartets.
In a letter to the Viennese publisher Artaria, Haydn described the Op. 33 quartets as "a new and entirely special kind." The letter is one of the few direct statements Haydn left about what distinguished this set from his earlier chamber works.
Many of the Op. 33 quartets, possibly all six, were premiered on Christmas Day, 1781, at the Viennese apartment of the Grand Duchess Maria Feodorovna, wife of Grand Duke Paul of Russia.