It has to do with Harry Potter though nothing to do with any wizard. Quoting myself from the usernames topic:
CauldronWench said:
I wanted Aris which is the username that I use most of the time but alas it was taken, so I ended up with good old Wenchie here. I moderate a forum called the Leaky Cauldron at a Harry Potter messageboard, hence the Cauldron part. And since The Leaky Cauldron in HP is a pub and wenches serve at pubs...well you get where I am going with this...