Romulus Augustus as Western Roman Emperor? He is judged by many historians to have been the last Western Roman Emperor. He was deposed by the "barbarian" Odoacer in 476, reigning less than a year.
The linked Wikipedia article says there is controversy about whether Romulus Augustus should be really considered the last true Western Roman Emperor since his reign was so short and because he was only a teenager (installed by his father, Orestes, a general, who really ran things, to the extent that they could be run in that time of collapse). Apparently, some historians would consider Romulus's predecessor, Julius Nepos, as a better candidate for the "last" emperor (even Odoacer claimed to be ruling in the name of Julius Nepos, at first).
But these historians have no sense of style. If Romulus Augustus hadn't existed, he'd have to have been invented: Named for the mythical founder (and first King) of Rome and for the first Emperor, poor little R.A. serves as a perfect punctuation mark for the end of classical Roman history and the start of Europe's Middle Ages. Sic transit gloria mundi.
Other observances today tend to tie more into Halloween.
For example, today is National Carmel Apple Day. It's also Magic Day -- and (probably related) today is the anniversary of the date on which Harry Houdini died (in 1926).
In what surely would have been his greatest escape, Houdini promised to communicate from beyond the grave -- if he could. So far... nothing.
It's a shame, of course, but magic is bunk.
How can we say this with such authority? Well, today is also National Knock Knock Joke Day. If magic were real, surely someone would have made knock-knock jokes disappear by now.