XLIX happy leap!

Leap year did not do Frederick any good,
He was bound both by duty and tight pants,
If you do not know what I mean, you should,
Go forth and watch thee Pirates of Penzance!
Or horror films get large prophetic kicks
From days that show up four years at a time,
Like Jeepers Creepers (quite a dreadful flick)
Just trust me, I have seen it, it's a crime.
It seems to me an awful lot of work,
Just to keep some calendars organized,
I hope Gregorians got lots of perks,
For keeping all those numbers memorized.
   It may be accruing a cheap patina,
   But oh, it gives great Deus Ex Machina.