For Perl history buffs, there is a wealth of information available in this long London.pm 25 Years of Perl mailing list thread.
Though there are a number of Perl talks available at Shadowcat Systems LPW 2012 youtube channel, I couldn't find davorg's "25 Years of Perl" talk among them.
See also a detailed article at the Perl Foundation: The First Twenty-Five Years by Mark Keating (mdk)
By rote learning.
Via Genetic memory.
It's provided by my firmware.
I just remember them.
Thirty days hath September
My computer gets it right, usually.
I just ask someone else.
Someone punches me on the first of the month.
Results (120 votes),