Consider a simple screening, the FizzBuzz Test. I recently was presented this in an interview and later I found out that this is a powerful test !!. The interviewer wanted to see how Perlish my reply can get :p..

Another thing, if this interview is Perl related, the interviewer might want to check how you approach CPAN/modules to address a programming situation by putting you in such a perspective.

I found the FizzBuzz test absolutely hilarious and time-saving...

Good luck ...