Breaux Vineyards, 17th Annual Cajun Festival and Crawfish Boil http://www.breauxvineyards.com/scripts/ ... fish-Boil/
On Harpers Ferry Road, north of Purcellville. I have been told by a die hard Cajun that they have good Gumbo.
Also just south of there at the intersection of Harpers Ferry Road (Rt 671) and Charles Town Pike (Rt 9) is some excellent roadside BBQ.