The calling out of paint duels, side challenges, and grudge matches extends from the earliest editions of the Challenge, and have become a time-honoured tradition - an established part of Challenge lore.
These affairs de la brosse are meant to keep participants motivated over the three months of the Challenge, and create a fun atmosphere of smack-talk, brush-baiting and ridiculous paint vendettas.
For those who are new to this silliness, the paint duels allow a pair of individuals or small groups to test one another against a self-defined set of criteria. Maybe it's to see who can paint the most points of a specific type of model over the length of the Challenge (i.e. The Ship Challenge), or who can paint the most figures in the most periods/genres (i.e. The Squirrel Duels); other side challenges might be created to see who can reach a specific points threshold first (Points Race). The sky's the limit - really, it's up to your imagination.
Simply issue your challenge down in the comments and see if other Challengers take up your gauntlet. I suggest that those involved keep close track of their duels themselves, producing updates on the blog to keep the rest of us informed and amused. If there is enough interest, we may assign a minion to help provide periodic updates on the duels (casting my eye over the oar benches...) on our special page dedicated for this! You can find the link to the Duels page on the top navigation bar to see previous year's events.