Honestly, for sharpening your Perl skills, you can't do better than participating in Perl Monks. Fresh new questions every day!

I am very skeptical of the pedagogical value of quizzes. It is very difficult to write a quiz suitable for automated grading (e.g. multiple choice) without resorting to curiosities and arcana. They may give you some new stunts to pull off at the next golf tournament or obfu contest, but they won't really make you a better programmer.

In contrast, what you learn from the give-and-take of PM is much richer and relevant to your development as a programmer.

So, stick around. :-)