FTP, name this work featured in 2001:
When Brahms was asked for his autograph by the daughter of this work's composer, he wrote out a few bars of it and wrote, "Sadly, not by Johannes Brahms." Written in 1867 in response to a commission by the Vienna Men's Chorus Association, it was originally a choral work of four waltz numbers, to which the composer added a piano accompaniment.  A fifth number was later added, words were provided by Josef Weyl, and the more familiar orchestral version appeared in the same year.  FTP, name this work featured in 2001: A Space Odyssey and countless commercials, probably the most famous waltz of Johann Strauss, Jr.
When Brahms was asked for his autograph by the daughter of this work's composer, he wrote out a few bars of it and wrote, "Sadly, not by Johannes Brahms.
By the Beautiful Blue Danube waltz or An der schoenen blauen Donau or Op. 314 (prompt on Strauss before "its composer" is read)