Spread the joy of the Canterbury Faire postal service by giving the couriers letters for random delivery. Make someone's day with real mail: your letter could quote a sonnet, contain a sketch, a report from the scene of a battle or a celebration, well wishes, a riddle to puzzle over, a historical factoid.
Try to keep it suitable for any recipient, or note if it would be best given to a lady, an artisan, a fighter, a person at their first Faire etc.
Leave your letter anonymous or see if the unknown recipient can puzzle out your seal, sigil or signature.
Prepare a set of cheerful, uplifting notes today, bring them to Faire and hand over your efforts to Postmaster-General Lord Zoltan di Magnifico or leave at the Green Man postal depot for their random distribution (no stamp duty will be charged).
If you'd like an idea of how to pen or fold such a letter, along with instructions on putting together a period-style thank-you note, check this out: