This weekend, Chicago’s annual art fair kicks off. And so does Chicago’s other annual art fair. Oh, and the other one, too. In fact, the heated competition between two established fairs and one new upstart is garnering international attention, as lawsuits are filed, dates are juggled, and trash is talked. It’s a full-fledged art war, and while no one seems to be sure whether such a thing is actually good for art, it’s damned entertaining to watch.