Long cast as the home of hospitality, green tomatoes, and civil war memorials, the South is pushing back against a more current War of Northern Aggression. Gaming expos born north of Mason-Dixon line have prospered: Penny Arcade Expo began in 2004 outside of Bellevue, Washington before expanding to Boston, Australia, and Texas. Gen Con, founded in Wisconsin by the father of Dungeons & Dragons, Gary Gygax, focuses on tabletop gaming and calls Indiana home. The largest and oldest retro games convention is still California Extreme, set in Santa Clara the past 20 years. But Southerners love games, too. And Preston…