I've just finished a hat for Hat Attack, which is sort of like Dueling Club for Muggles. The structure is a bit different - instead of a one-to-one matchup, everyone's in a chain, trying to do in the next person down. Imagine being in a Quiddtich match where there aren't any teams, and everyone's looking for the Snitch!
My hat is in the mail now, on its way to "kill" my Muggle victim. Muggle knitters can be a pretty violent bunch. I wonder if it's because they only get to wave around knitting needles, and never wands?