Anything applicable to Computer Science (algorithm, theory, practice, NP complete discussions, etc) or to work involving Perl (project management, how much beer makes you a better hacker or does it, keyboard selection, glued languages, editors...) seems the complete range of Off-Topic that would be acceptable and does range very far afield but still might belong here or help other monks.
Dating, politics, cooking... Unless you're dating another monk or running for chair of the EPO or cooking a monk... That's why one Facebooks or Tumblrs or Reddits.
I don't think we need a guide. Off-topic is like pornography. Not just that one knows it when one sees it but what was pr0n 30 years ago is just about PG-13 today. Off-topic today might not feel like off-topic tomorrow.