Events in Music that are not possible. '''only list examples that fit this description'''

* The first movement of {{Beethoven}}'s ''Pathetique Sonata'' has ''128th-note'' chromatic glissandos. The third movement of ''Moonlight Sonata'' has a "Presto Agitato" (read: damn fast) tempo and 16th-note arpeggios, nearly impossible to play by human hands. Some pieces composed after he went deaf are literally unplayable.
** In the same vein, "[[http://www.youtube.com/watch?v=6utk2nFjpXA Circus Galop]]" by [[http://en.wikipedia.org/wiki/Marc-Andr%C3%A9_Hamelin Marc-André Hamelin]], which is playable if you can find two people whose thumb-and-pinky stretch is 13 or 14 inches. In fairness, Hamelin wrote the thing for self-playing piano, and it is not ''meant'' to be performed by wetware.
** Near the end of the middle section in Modest Mussorgsky's "The Hut of Baba Yaga", the left-hand pattern changes from 16th-note triplets to what are notated as ''64th-note'' tremolos. It is assumed that these should merely be played as fast as possible.
* ShawnLane's [[http://www.youtube.com/watch?v=WhTHxkIllvU guitar playing]] and {{Buckethead}} figuring out how to play a song that Shawn wrote to specifically NOT be playable. Shawn Lane made a recording by playing one note at a time on a guitar and then stitching them together impossibly fast, at impossibly wide intervals, that he was sure no human could play. Buckethead, [[AchievementsInIgnorance thinking it was a legit recording]], then proceeded to figure out how to play it for real and IN REAL TIME.
** Tim Miller falls into a similar category for different reasons. He doesn't often play impossibly fast, he just plays lines that come from a system he developed and thus are harmonically near-impossible to conceive of for guitarists who aren't him. It does indeed hit the ear incredibly strangely. [[note]]Shawn Lane notably is still the fastest guitarist in terms of notes per second played in a controlled fashion. Some guitarists can play more notes per second, but they can't maintain rhythm while doing it. Theoretically speaking, some of his work is impossible to play until anyone else develops the same level of controlled speed. [[/note]]
* Robert Schumann's Piano Sonata No. 2 in G minor infamously tells the pianist to play faster in the coda of the first movement, whose base tempo is already "so rasch wie möglich" (as fast as possible).
* Subverted by the opening chord to TheBeatles' song "A Hard Day's Night." It took more than 40 years for audio analysis technology to reproduce it because the key discovery that some of the sound was not made by a guitar.
* Conlon Nancarrow composed music involving complex mathematical ratios and impossibly fast tempos specifically designed to be unplayable by humans. (For instance, one piece has two different simultaneous tempos in the ratio ''e'' : π.) He realized them by means of custom-made player piano rolls.