Tapestry of bronze is a website dedicated to the Gods of ancient Greece. Every six months they run a free poetry competition dedicated to one of the aforementioned deities. Last time around it was Demeter (Ceres) and I entered. Didn't get anywhere but at least I learned something about Demeter (never could answer the Ancient Greece questions on Mastermind)
This time its Hermes or Mercury, nubile cattle-thief and tortoise murderer (see, I've been researching)
Closing date 30th April but email submissions accepted. Full details here
Did I mention it was free?