I'm not much of a teacher. But if I were teaching a brief overview of Perl, I would probably follow the outline of perlintro. It's all there:

• What is Perl?
• Running Perl programs
• Basic syntax overview
• Perl variable types
• Variable scoping
• Conditional and looping constructs
• Builtin operators and functions
• Files and I/O
• Regular expressions
• Writing subroutines
• OO Perl
• Using Perl modules

The section on OO Perl is very brief, mostly just mentioning that it's beyond the scope of the article, but that the "Using Perl modules" section would at least address how to deal with OO modules.

That ought to be good meat and potatos to get the group started. The next day, pick one of the topics from perlintro, and dive into it in greater depth. perlsyn and perlsub may be a good basis for the second and third sessions. perlretut or perlreftut might make a good week-two discussion.