I haven't ever made a Gen Con, alone among the major cons over the years. Primarily it has been an RPG-oriented event and that's just a minor interest of mine.
Still, it's a major con, so word it has filed for bankruptcy is of interest. Some info is here: http://purplepawn.com/2008/05/12/why-gen-con-went-bankrupt/ but the bottom line is that the con has a couple million dollars in debts, which seems like a pretty big amount to me. I had no idea that convention budgets could add up to such huge numbers these days. Fascinating.