Used sarcastically to describe things of a ghetto or trailer-park nature. Often means the opposite of Paris Hilton's "that's hott."
Keisha: "Do these pink assless pants look good with this see-through purple shirt and these plastic platform heels?"
Rhett: "Yes, they look quite classy!"
Christine: "Shannon, could you grab me that there corndog out of my purse?"
Shannon: "Bringing a corndog to Great Aunt Lizzie's funeral? That's classy Christine, real classy."