When I teach a Perl course, I tell them about arrays and hashes on the afternoon of the first day. Even before control structures like if and while (that's the morning of the second day).

And in the morning of the first day, we talk about the history of Perl, the manual, CPAN, the manual, mailing lists, the manual, websites, use strict, the manual, use warnings, the manual, and how to run a Perl program. Oh, and how to use the manual of course.

Abigail