For those that are struggling for puzzles, projects ideas and, generally, things to do with Perl, I provide this link.

So, what's HAKMEM?

Work reported herein was conducted at the Artificial Intelligence Laboratory, a Massachusetts Institute of Technology research program supported in part by the Advanced Research Projects Agency of the Department of Defense and monitored by the Office of Naval Research under Contract Number N00014-70-A-0362-0002.
I suggest digging in the stuff provided: I bet you'll find something interesting for you. Problems vary from Number Theory, Primes, Probability to Proposed Computer Programs (such as Solve Go :))